| 1966-04-12 | vs DET | 1 | L 1-2 | 0-1 | 7 | 40,006 | Whitey Ford | Mickey Lolich | Mickey Lolich | Whitey Ford | | 1 | 2 | -1 |
| 1966-04-14 | vs DET | 2 | L 2-3 | 0-3 | 8 | 0 | Mel Stottlemyre | Denny McLain | Denny McLain | Pedro Ramos | Larry Sherry | 3 | 5 | -2 |
| 1966-04-14 | vs DET | 3 | L 2-5 | 0-3 | 8 | 13,659 | Bob Friend | Bill Monbouquette | Bill Monbouquette | Bob Friend | | 5 | 10 | -5 |
| 1966-04-15 | @ BAL | 4 | W 3-2 | 1-3 | 7 | 35,624 | Fritz Peterson | Wally Bunker | Fritz Peterson | Wally Bunker | | 8 | 12 | -4 |
| 1966-04-16 | @ BAL | 5 | L 2-7 | 1-4 | 7 | 12,128 | Al Downing | Dave McNally | Dave McNally | Al Downing | Stu Miller | 10 | 19 | -9 |
| 1966-04-17 | @ BAL | 6 | L 4-5 | 1-5 | 8 | 27,802 | Whitey Ford | Steve Barber | Dick Hall | Pedro Ramos | Stu Miller | 14 | 24 | -10 |
| 1966-04-19 | @ CLE | 7 | L 1-3 | 1-6 | 9 | 6,541 | Mel Stottlemyre | Sam McDowell | Sam McDowell | Mel Stottlemyre | | 15 | 27 | -12 |
| 1966-04-20 | @ CLE | 8 | L 2-4 | 1-7 | 10 | 11,482 | Bob Friend | Sonny Siebert | John O'Donoghue | Pedro Ramos | | 17 | 31 | -14 |
| 1966-04-23 | vs BAL | 9 | L 3-4 | 1-8 | 10 | 17,099 | Fritz Peterson | Dave McNally | Dave McNally | Fritz Peterson | Stu Miller | 20 | 35 | -15 |
| 1966-04-24 | vs BAL | 10 | L 1-2 | 1-9 | 10 | 13,104 | Mel Stottlemyre | Steve Barber | Steve Barber | Mel Stottlemyre | | 21 | 37 | -16 |
| 1966-04-25 | vs BOS | 11 | L 5-8 | 1-10 | 10 | 3,370 | Bob Friend | Earl Wilson | Ken Sanders | Bob Friend | | 26 | 45 | -19 |
| 1966-04-26 | vs BOS | 12 | W 7-6 | 2-10 | 10 | 9,457 | Whitey Ford | Jim Lonborg | Dooley Womack | Ken Sanders | | 33 | 51 | -18 |
| 1966-04-27 | vs WS2 | 13 | L 0-2 | 2-11 | 10 | 3,185 | Al Downing | Mike McCormick | Mike McCormick | Al Downing | | 33 | 53 | -20 |
| 1966-04-30 | vs KC1 | 14 | W 6-0 | 3-11 | 9 | 11,416 | Mel Stottlemyre | Fred Talbot | Mel Stottlemyre | Fred Talbot | | 39 | 53 | -14 |
| 1966-05-01 | vs KC1 | 15 | L 0-1 | 4-12 | 9 | 0 | Whitey Ford | Rollie Sheldon | Rollie Sheldon | Whitey Ford | | 39 | 54 | -15 |
| 1966-05-01 | vs KC1 | 16 | W 10-4 | 4-12 | 9 | 17,387 | Fritz Peterson | Chuck Dobson | Jack Cullen | Lew Krausse | | 49 | 58 | -9 |
| 1966-05-03 | vs CLE | 17 | L 0-1 | 4-13 | 9 | 11,275 | Al Downing | Luis Tiant | Luis Tiant | Al Downing | | 49 | 59 | -10 |
| 1966-05-04 | vs CLE | 18 | L 1-2 | 4-14 | 9 | 11,861 | Mel Stottlemyre | Sonny Siebert | Sonny Siebert | Steve Hamilton | | 50 | 61 | -11 |
| 1966-05-05 | vs CLE | 19 | L 0-4 | 4-15 | 9 | 12,730 | Bob Friend | John O'Donoghue | John O'Donoghue | Bob Friend | Bob Allen | 50 | 65 | -15 |
| 1966-05-06 | @ CAL | 20 | L 4-7 | 4-16 | 10 | 31,690 | Whitey Ford | George Brunet | Jack Sanford | Whitey Ford | Lew Burdette | 54 | 72 | -18 |
| 1966-05-07 | @ CAL | 21 | W 3-1 | 5-16 | 10 | 42,851 | Fritz Peterson | Marcelino Lopez | Fritz Peterson | Marcelino Lopez | | 57 | 73 | -16 |
| 1966-05-08 | @ CAL | 22 | W 5-2 | 6-16 | 9 | 26,260 | Al Downing | Dean Chance | Al Downing | Dean Chance | Pedro Ramos | 62 | 75 | -13 |
| 1966-05-09 | @ MIN | 23 | W 3-2 | 7-16 | 9 | 10,129 | Mel Stottlemyre | Jim Perry | Mel Stottlemyre | Al Worthington | | 65 | 77 | -12 |
| 1966-05-12 | @ MIN | 24 | L 3-4 | 7-17 | 9 | 10,743 | Fritz Peterson | Camilo Pascual | Camilo Pascual | Fritz Peterson | Jim Merritt | 68 | 81 | -13 |
| 1966-05-13 | @ KC1 | 25 | W 4-2 | 8-17 | 9 | 9,619 | Whitey Ford | Chuck Dobson | Steve Hamilton | Chuck Dobson | Pedro Ramos | 72 | 83 | -11 |
| 1966-05-14 | @ KC1 | 26 | L 2-4 | 8-18 | 9 | 12,258 | Mel Stottlemyre | Fred Talbot | Fred Talbot | Mel Stottlemyre | Jack Aker | 74 | 87 | -13 |
| 1966-05-15 | @ KC1 | 27 | W 5-2 | 10-18 | 8 | 0 | Al Downing | Rollie Sheldon | Al Downing | Rollie Sheldon | Pedro Ramos | 79 | 89 | -10 |
| 1966-05-15 | @ KC1 | 28 | W 3-1 | 10-18 | 8 | 32,088 | Bob Friend | Ralph Terry | Bob Friend | Ralph Terry | Pedro Ramos | 82 | 90 | -8 |
| 1966-05-17 | @ DET | 29 | L 2-7 | 10-19 | 8 | 9,935 | Fritz Peterson | Denny McLain | Denny McLain | Fritz Peterson | | 84 | 97 | -13 |
| 1966-05-18 | @ DET | 30 | W 7-2 | 11-19 | 9 | 14,010 | Mel Stottlemyre | Mickey Lolich | Mel Stottlemyre | Mickey Lolich | | 91 | 99 | -8 |
| 1966-05-20 | vs MIN | 31 | W 2-1 | 12-19 | 8 | 21,908 | Al Downing | Camilo Pascual | Al Downing | Camilo Pascual | Pedro Ramos | 93 | 100 | -7 |
| 1966-05-21 | vs MIN | 32 | W 4-2 | 13-19 | 8 | 29,803 | Bob Friend | Jim Kaat | Steve Hamilton | Jim Kaat | | 97 | 102 | -5 |
| 1966-05-22 | vs MIN | 33 | W 5-3 | 15-19 | 7 | 0 | Mel Stottlemyre | Mudcat Grant | Mel Stottlemyre | Mudcat Grant | Pedro Ramos | 102 | 105 | -3 |
| 1966-05-22 | vs MIN | 34 | W 2-1 | 15-19 | 7 | 36,261 | Fritz Peterson | Jim Merritt | Fritz Peterson | Jim Merritt | Pedro Ramos | 104 | 106 | -2 |
| 1966-05-24 | vs CAL | 35 | L 2-4 | 15-20 | 8 | 12,187 | Whitey Ford | Jack Sanford | George Brunet | Dooley Womack | | 106 | 110 | -4 |
| 1966-05-25 | vs CAL | 36 | W 11-6 | 16-20 | 7 | 11,643 | Al Downing | Dean Chance | Al Downing | Dean Chance | Pedro Ramos | 117 | 116 | 1 |
| 1966-05-27 | vs CHA | 37 | W 4-1 | 17-20 | 6 | 14,240 | Mel Stottlemyre | Joe Horlen | Mel Stottlemyre | Joe Horlen | | 121 | 117 | 4 |
| 1966-05-28 | vs CHA | 38 | W 2-2 | 18-20 | 5 | 14,622 | Fritz Peterson | Bruce Howard | | | | 123 | 119 | 4 |
| 1966-05-29 | vs CHA | 39 | L 0-2 | 18-21 | 6 | 32,989 | Bob Friend | Tommy John | Tommy John | Bob Friend | | 123 | 121 | 2 |
| 1966-05-30 | @ WS2 | 40 | W 4-2 | 19-22 | 7 | 0 | Al Downing | Mike McCormick | Al Downing | Mike McCormick | Hal Reniff | 127 | 123 | 4 |
| 1966-05-30 | @ WS2 | 41 | L 1-2 | 19-22 | 7 | 31,764 | Jim Bouton | Diego Segui | Diego Segui | Pedro Ramos | Ron Kline | 128 | 125 | 3 |
| 1966-05-31 | @ WS2 | 42 | L 1-5 | 19-23 | 8 | 10,726 | Mel Stottlemyre | Pete Richert | Pete Richert | Mel Stottlemyre | | 129 | 130 | -1 |
| 1966-06-01 | @ CHA | 43 | L 2-6 | 19-24 | 8 | 21,637 | Fritz Peterson | Juan Pizarro | Juan Pizarro | Fritz Peterson | Eddie Fisher | 131 | 136 | -5 |
| 1966-06-02 | @ CHA | 44 | W 5-3 | 20-24 | 8 | 8,650 | Bob Friend | Tommy John | Steve Hamilton | Tommy John | | 136 | 139 | -3 |
| 1966-06-03 | @ BOS | 45 | W 15-5 | 21-24 | 7 | 27,196 | Al Downing | Earl Wilson | Al Downing | Earl Wilson | | 151 | 144 | 7 |
| 1966-06-04 | @ BOS | 46 | L 3-6 | 21-25 | 7 | 21,897 | Mel Stottlemyre | Jose Santiago | Ken Sanders | Dooley Womack | | 154 | 150 | 4 |
| 1966-06-05 | @ BOS | 47 | W 5-3 | 22-25 | 6 | 21,593 | Jim Bouton | Jim Lonborg | Jim Bouton | Jim Lonborg | Pedro Ramos | 159 | 153 | 6 |
| 1966-06-07 | @ CLE | 48 | W 7-2 | 23-25 | 6 | 12,572 | Fritz Peterson | John O'Donoghue | Fritz Peterson | John O'Donoghue | | 166 | 155 | 11 |
| 1966-06-08 | @ CLE | 49 | L 1-2 | 23-26 | 6 | 15,191 | Mel Stottlemyre | Gary Bell | Gary Bell | Mel Stottlemyre | Sam McDowell | 167 | 157 | 10 |
| 1966-06-10 | @ DET | 50 | L 2-6 | 23-27 | 7 | 29,674 | Jim Bouton | Hank Aguirre | Hank Aguirre | Jim Bouton | | 169 | 163 | 6 |
| 1966-06-11 | @ DET | 51 | W 6-3 | 24-27 | 7 | 17,104 | Fritz Peterson | Joe Sparma | Fritz Peterson | Joe Sparma | Hal Reniff | 175 | 166 | 9 |
| 1966-06-12 | @ DET | 52 | L 5-7 | 25-28 | 7 | 0 | Mel Stottlemyre | Denny McLain | Denny McLain | Mel Stottlemyre | Larry Sherry | 180 | 173 | 7 |
| 1966-06-12 | @ DET | 53 | W 12-10 | 25-28 | 7 | 41,421 | Fred Talbot | Mickey Lolich | Steve Hamilton | Mickey Lolich | Hal Reniff | 192 | 183 | 9 |
| 1966-06-13 | @ BAL | 54 | L 0-8 | 25-29 | 7 | 28,225 | Al Downing | Jim Palmer | Jim Palmer | Al Downing | Eddie Watt | 192 | 191 | 1 |
| 1966-06-14 | @ BAL | 55 | L 1-2 | 25-30 | 7 | 37,891 | Jim Bouton | Dave McNally | Stu Miller | Jim Bouton | | 193 | 193 | 0 |
| 1966-06-15 | vs CLE | 56 | L 5-8 | 25-31 | 7 | 18,215 | Fritz Peterson | John O'Donoghue | John O'Donoghue | Fritz Peterson | Bob Allen | 198 | 201 | -3 |
| 1966-06-16 | vs CLE | 57 | W 7-6 | 26-31 | 7 | 12,530 | Fred Talbot | Sam McDowell | Fred Talbot | Sam McDowell | Hal Reniff | 205 | 207 | -2 |
| 1966-06-17 | vs DET | 58 | W 5-2 | 27-31 | 7 | 18,357 | Mel Stottlemyre | Earl Wilson | Mel Stottlemyre | Earl Wilson | | 210 | 209 | 1 |
| 1966-06-18 | vs DET | 59 | L 3-4 | 27-32 | 7 | 26,565 | Al Downing | Hank Aguirre | Bill Monbouquette | Pedro Ramos | Larry Sherry | 213 | 213 | 0 |
| 1966-06-19 | vs DET | 60 | L 1-2 | 27-33 | 7 | 61,071 | Jim Bouton | Dave Wickersham | Dave Wickersham | Jim Bouton | | 214 | 215 | -1 |
| 1966-06-21 | vs BAL | 61 | L 5-7 | 28-34 | 7 | 0 | Mel Stottlemyre | Wally Bunker | Wally Bunker | Mel Stottlemyre | Stu Miller | 219 | 222 | -3 |
| 1966-06-21 | vs BAL | 62 | W 8-3 | 28-34 | 7 | 29,449 | Fritz Peterson | Frank Bertaina | Hal Reniff | Frank Bertaina | | 227 | 225 | 2 |
| 1966-06-22 | vs BAL | 63 | L 0-3 | 28-35 | 7 | 17,239 | Fred Talbot | Steve Barber | Steve Barber | Fred Talbot | | 227 | 228 | -1 |
| 1966-06-23 | vs BAL | 64 | L 2-5 | 28-36 | 7 | 10,640 | Al Downing | Jim Palmer | Jim Palmer | Al Downing | Eddie Fisher | 229 | 233 | -4 |
| 1966-06-24 | vs CHA | 65 | W 5-2 | 29-36 | 7 | 16,834 | Jim Bouton | Juan Pizarro | Steve Hamilton | Juan Pizarro | Hal Reniff | 234 | 235 | -1 |
| 1966-06-25 | vs CHA | 66 | L 1-2 | 29-37 | 7 | 27,098 | Mel Stottlemyre | Gary Peters | Gary Peters | Mel Stottlemyre | Bob Locker | 235 | 237 | -2 |
| 1966-06-26 | vs CHA | 67 | W 7-2 | 31-37 | 7 | 0 | Fred Talbot | Tommy John | Fred Talbot | Tommy John | | 242 | 239 | 3 |
| 1966-06-26 | vs CHA | 68 | W 2-0 | 31-37 | 7 | 27,893 | Fritz Peterson | Joe Horlen | Fritz Peterson | Joe Horlen | | 244 | 239 | 5 |
| 1966-06-28 | @ BOS | 69 | L 3-5 | 31-38 | 7 | 14,922 | Al Downing | Jose Santiago | Jose Santiago | Al Downing | | 247 | 244 | 3 |
| 1966-06-29 | @ BOS | 70 | W 6-5 | 32-38 | 7 | 14,614 | Mel Stottlemyre | Rollie Sheldon | Mel Stottlemyre | Rollie Sheldon | Hal Reniff | 253 | 249 | 4 |
| 1966-06-30 | @ BOS | 71 | L 2-3 | 32-39 | 7 | 12,727 | Jim Bouton | Jim Lonborg | Don McMahon | Hal Reniff | | 255 | 252 | 3 |
| 1966-07-01 | @ WS2 | 72 | W 8-6 | 33-39 | 7 | 16,104 | Fred Talbot | Phil Ortega | Fred Talbot | Phil Ortega | Pedro Ramos | 263 | 258 | 5 |
| 1966-07-02 | @ WS2 | 73 | L 4-10 | 33-40 | 7 | 7,197 | Whitey Ford | Mike McCormick | Mike McCormick | Whitey Ford | | 267 | 268 | -1 |
| 1966-07-03 | @ WS2 | 74 | W 6-5 | 34-40 | 6 | 16,760 | Al Downing | Pete Richert | Pedro Ramos | Ron Kline | | 273 | 273 | 0 |
| 1966-07-04 | vs CHA | 75 | L 0-5 | 35-41 | 6 | 0 | Mel Stottlemyre | Gary Peters | Gary Peters | Mel Stottlemyre | | 273 | 278 | -5 |
| 1966-07-04 | vs CHA | 76 | W 5-2 | 35-41 | 6 | 18,313 | Fritz Peterson | Juan Pizarro | Fritz Peterson | Juan Pizarro | | 278 | 280 | -2 |
| 1966-07-05 | vs BOS | 77 | L 1-7 | 35-42 | 7 | 12,629 | Fred Talbot | Bucky Brandon | Bucky Brandon | Fred Talbot | | 279 | 287 | -8 |
| 1966-07-06 | vs BOS | 78 | L 3-5 | 35-44 | 8 | 0 | Whitey Ford | Jose Santiago | Don McMahon | Pedro Ramos | John Wyatt | 282 | 292 | -10 |
| 1966-07-06 | vs BOS | 79 | L 4-5 | 35-44 | 8 | 20,476 | Jim Bouton | Dave Morehead | Don McMahon | Hal Reniff | John Wyatt | 286 | 297 | -11 |
| 1966-07-07 | vs BOS | 80 | W 5-2 | 36-44 | 7 | 12,711 | Al Downing | Rollie Sheldon | Dooley Womack | Don McMahon | | 291 | 299 | -8 |
| 1966-07-08 | vs WS2 | 81 | L 6-7 | 37-45 | 7 | 0 | Mel Stottlemyre | Dick Bosman | Dick Lines | Mel Stottlemyre | Ron Kline | 297 | 306 | -9 |
| 1966-07-08 | vs WS2 | 82 | W 7-5 | 37-45 | 7 | 14,863 | Fritz Peterson | Jim Hannan | Fritz Peterson | Dick Bosman | | 304 | 311 | -7 |
| 1966-07-09 | vs WS2 | 83 | L 0-3 | 37-46 | 7 | 23,716 | Fred Talbot | Diego Segui | Diego Segui | Fred Talbot | | 304 | 314 | -10 |
| 1966-07-10 | vs WS2 | 84 | L 2-3 | 37-48 | 9 | 0 | Jim Bouton | Mike McCormick | Mike McCormick | Jim Bouton | Ron Kline | 306 | 317 | -11 |
| 1966-07-10 | vs WS2 | 85 | L 2-9 | 37-48 | 9 | 16,471 | Dooley Womack | Bob Humphreys | Bob Humphreys | Dooley Womack | Casey Cox | 308 | 326 | -18 |
| 1966-07-14 | @ KC1 | 86 | W 5-4 | 38-48 | 8 | 20,197 | Al Downing | Catfish Hunter | Pedro Ramos | Guido Grilli | | 313 | 330 | -17 |
| 1966-07-15 | @ KC1 | 87 | L 4-5 | 38-49 | 8 | 23,229 | Mel Stottlemyre | Lew Krausse | Ken Sanders | Mel Stottlemyre | Jack Aker | 317 | 335 | -18 |
| 1966-07-16 | @ KC1 | 88 | W 9-5 | 39-49 | 8 | 18,615 | Fritz Peterson | Paul Lindblad | Whitey Ford | Jack Aker | Pedro Ramos | 326 | 340 | -14 |
| 1966-07-17 | @ MIN | 89 | W 4-2 | 41-49 | 7 | 0 | Fred Talbot | Jim Merritt | Fred Talbot | Jim Merritt | Hal Reniff | 330 | 342 | -12 |
| 1966-07-17 | @ MIN | 90 | W 9-6 | 41-49 | 7 | 37,207 | Jim Bouton | Jim Perry | Steve Hamilton | Jim Perry | Pedro Ramos | 339 | 348 | -9 |
| 1966-07-18 | @ MIN | 91 | W 6-4 | 42-49 | 6 | 18,604 | Al Downing | Mudcat Grant | Hal Reniff | Pete Cimino | | 345 | 352 | -7 |
| 1966-07-20 | vs KC1 | 92 | W 4-0 | 43-49 | 7 | 14,871 | Mel Stottlemyre | Catfish Hunter | Mel Stottlemyre | Catfish Hunter | | 349 | 352 | -3 |
| 1966-07-21 | vs KC1 | 93 | W 4-3 | 44-49 | 7 | 18,413 | Fritz Peterson | Lew Krausse | Pedro Ramos | Jack Aker | | 353 | 355 | -2 |
| 1966-07-22 | vs CAL | 94 | L 4-6 | 44-50 | 7 | 16,450 | Fred Talbot | Clyde Wright | Lew Burdette | Jim Bouton | | 357 | 361 | -4 |
| 1966-07-23 | vs CAL | 95 | L 6-7 | 44-51 | 7 | 34,042 | Al Downing | Marcelino Lopez | Minnie Rojas | Whitey Ford | | 363 | 368 | -5 |
| 1966-07-24 | vs CAL | 96 | W 9-1 | 46-51 | 6 | 0 | Mel Stottlemyre | George Brunet | Mel Stottlemyre | George Brunet | | 372 | 369 | 3 |
| 1966-07-24 | vs CAL | 97 | W 4-1 | 46-51 | 6 | 23,534 | Steve Hamilton | Dean Chance | Dooley Womack | Dean Chance | Pedro Ramos | 376 | 370 | 6 |
| 1966-07-26 | vs MIN | 98 | L 3-6 | 46-52 | 6 | 17,811 | Fritz Peterson | Dave Boswell | Dave Boswell | Fritz Peterson | Al Worthington | 379 | 376 | 3 |
| 1966-07-27 | vs MIN | 99 | W 6-3 | 47-52 | 6 | 19,960 | Fred Talbot | Jim Kaat | Fred Talbot | Jim Kaat | | 385 | 379 | 6 |
| 1966-07-29 | @ CHA | 100 | W 2-1 | 48-52 | 6 | 30,364 | Al Downing | Bruce Howard | Al Downing | Bruce Howard | Hal Reniff | 387 | 380 | 7 |
| 1966-07-30 | @ CHA | 101 | L 0-6 | 48-53 | 7 | 16,767 | Mel Stottlemyre | Gary Peters | Gary Peters | Mel Stottlemyre | | 387 | 386 | 1 |
| 1966-07-31 | @ CHA | 102 | L 1-4 | 48-55 | 7 | 0 | Fritz Peterson | Joe Horlen | Joe Horlen | Fritz Peterson | | 388 | 390 | -2 |
| 1966-07-31 | @ CHA | 103 | L 0-5 | 48-55 | 7 | 36,884 | Steve Hamilton | Tommy John | Tommy John | Steve Hamilton | | 388 | 395 | -7 |
| 1966-08-01 | @ CAL | 104 | L 3-4 | 48-56 | 7 | 21,967 | Fred Talbot | Clyde Wright | Jack Sanford | Hal Reniff | Lew Burdette | 391 | 399 | -8 |
| 1966-08-02 | @ CAL | 105 | L 5-6 | 48-57 | 7 | 25,465 | Al Downing | George Brunet | Minnie Rojas | Hal Reniff | | 396 | 405 | -9 |
| 1966-08-03 | @ CAL | 106 | W 9-0 | 49-57 | 7 | 32,423 | Mel Stottlemyre | Dean Chance | Mel Stottlemyre | Dean Chance | | 405 | 405 | 0 |
| 1966-08-04 | @ CAL | 107 | L 7-11 | 49-58 | 7 | 19,512 | Fritz Peterson | Marcelino Lopez | Jack Sanford | Pedro Ramos | | 412 | 416 | -4 |
| 1966-08-05 | @ CLE | 108 | L 4-5 | 50-59 | 7 | 0 | Fred Talbot | Steve Hargan | Steve Hargan | Fred Talbot | Luis Tiant | 416 | 421 | -5 |
| 1966-08-05 | @ CLE | 109 | W 3-0 | 50-59 | 7 | 26,623 | Steve Hamilton | John O'Donoghue | Steve Hamilton | John O'Donoghue | | 419 | 421 | -2 |
| 1966-08-06 | @ CLE | 110 | W 5-4 | 51-59 | 7 | 24,144 | Jim Bouton | Sam McDowell | Whitey Ford | Luis Tiant | | 424 | 425 | -1 |
| 1966-08-07 | @ CLE | 111 | L 4-6 | 51-61 | 7 | 0 | Mel Stottlemyre | Sonny Siebert | Sonny Siebert | Mel Stottlemyre | Bob Allen | 428 | 431 | -3 |
| 1966-08-07 | @ CLE | 112 | L 3-5 | 51-61 | 7 | 37,668 | Al Downing | Tom Kelley | Jack Kralick | Al Downing | | 431 | 436 | -5 |
| 1966-08-09 | vs BAL | 113 | W 4-1 | 52-61 | 7 | 21,109 | Fritz Peterson | Jim Palmer | Fritz Peterson | Jim Palmer | | 435 | 437 | -2 |
| 1966-08-10 | vs BAL | 114 | L 4-9 | 52-62 | 7 | 19,804 | Fred Talbot | Eddie Watt | Dick Hall | Fred Talbot | | 439 | 446 | -7 |
| 1966-08-11 | vs BAL | 115 | L 5-6 | 52-63 | 7 | 14,481 | Mel Stottlemyre | Dave McNally | Gene Brabender | Pedro Ramos | | 444 | 452 | -8 |
| 1966-08-12 | vs CLE | 116 | L 2-3 | 52-64 | 7 | 16,980 | Al Downing | Gary Bell | Gary Bell | Al Downing | Luis Tiant | 446 | 455 | -9 |
| 1966-08-13 | vs CLE | 117 | L 1-2 | 52-65 | 7 | 38,202 | Jim Bouton | Steve Hargan | Steve Hargan | Hal Reniff | | 447 | 457 | -10 |
| 1966-08-14 | vs CLE | 118 | W 7-3 | 54-65 | 7 | 0 | Fritz Peterson | Sam McDowell | Dooley Womack | Sam McDowell | | 454 | 460 | -6 |
| 1966-08-14 | vs CLE | 119 | W 6-4 | 54-65 | 7 | 31,948 | Fred Talbot | Jack Kralick | Steve Hamilton | Tom Kelley | | 460 | 464 | -4 |
| 1966-08-15 | @ DET | 120 | L 5-6 | 54-66 | 7 | 15,256 | Mel Stottlemyre | Mickey Lolich | Mickey Lolich | Mel Stottlemyre | Larry Sherry | 465 | 470 | -5 |
| 1966-08-16 | @ DET | 121 | L 3-6 | 54-67 | 7 | 17,395 | Al Downing | Johnny Podres | Bill Monbouquette | Hal Reniff | | 468 | 476 | -8 |
| 1966-08-17 | @ DET | 122 | L 2-4 | 54-68 | 7 | 18,823 | Jim Bouton | Earl Wilson | Earl Wilson | Jim Bouton | | 470 | 480 | -10 |
| 1966-08-19 | vs KC1 | 123 | W 7-5 | 55-69 | 7 | 0 | Fred Talbot | Jim Nash | Fred Talbot | Jim Nash | Dooley Womack | 477 | 485 | -8 |
| 1966-08-19 | vs KC1 | 124 | L 0-1 | 55-69 | 7 | 12,338 | Fritz Peterson | Lew Krausse | Lew Krausse | Fritz Peterson | Jack Aker | 477 | 486 | -9 |
| 1966-08-20 | vs KC1 | 125 | W 8-5 | 56-69 | 7 | 10,448 | Mel Stottlemyre | Gil Blanco | Mel Stottlemyre | Gil Blanco | Dooley Womack | 485 | 491 | -6 |
| 1966-08-21 | vs KC1 | 126 | W 7-3 | 57-69 | 7 | 18,260 | Al Downing | Blue Moon Odom | Al Downing | Blue Moon Odom | Steve Hamilton | 492 | 494 | -2 |
| 1966-08-23 | vs CAL | 127 | L 0-1 | 57-70 | 7 | 10,926 | Fritz Peterson | Dean Chance | Dean Chance | Fritz Peterson | | 492 | 495 | -3 |
| 1966-08-24 | vs CAL | 128 | L 1-2 | 57-71 | 7 | 14,070 | Fred Talbot | Fred Newman | Fred Newman | Fred Talbot | Jack Sanford | 493 | 497 | -4 |
| 1966-08-25 | vs CAL | 129 | L 1-5 | 57-72 | 8 | 19,843 | Mel Stottlemyre | George Brunet | George Brunet | Mel Stottlemyre | | 494 | 502 | -8 |
| 1966-08-26 | vs DET | 130 | W 6-5 | 58-72 | 8 | 14,856 | Al Downing | Earl Wilson | Hal Reniff | Hank Aguirre | | 500 | 507 | -7 |
| 1966-08-27 | vs DET | 131 | W 11-1 | 59-72 | 8 | 13,757 | Jim Bouton | Johnny Podres | Jim Bouton | Johnny Podres | | 511 | 508 | 3 |
| 1966-08-28 | vs DET | 132 | W 8-1 | 60-72 | 8 | 22,797 | Fritz Peterson | Mickey Lolich | Fritz Peterson | Mickey Lolich | | 519 | 509 | 10 |
| 1966-08-29 | @ KC1 | 133 | W 7-2 | 61-72 | 7 | 15,894 | Fred Talbot | Lew Krausse | Dooley Womack | Lew Krausse | Steve Hamilton | 526 | 511 | 15 |
| 1966-08-30 | @ KC1 | 134 | L 1-4 | 61-73 | 7 | 6,505 | Mel Stottlemyre | Blue Moon Odom | Blue Moon Odom | Mel Stottlemyre | | 527 | 515 | 12 |
| 1966-08-31 | @ CAL | 135 | L 2-5 | 61-74 | 7 | 21,163 | Al Downing | Dean Chance | Dean Chance | Al Downing | | 529 | 520 | 9 |
| 1966-09-01 | @ CAL | 136 | W 5-2 | 62-74 | 7 | 21,254 | Fritz Peterson | Marcelino Lopez | Fritz Peterson | Marcelino Lopez | Dooley Womack | 534 | 522 | 12 |
| 1966-09-02 | @ MIN | 137 | L 5-8 | 62-75 | 7 | 18,999 | Jim Bouton | Mudcat Grant | Mudcat Grant | Steve Hamilton | Al Worthington | 539 | 530 | 9 |
| 1966-09-03 | @ MIN | 138 | L 1-6 | 63-76 | 7 | 19,630 | Fred Talbot | Jim Perry | Jim Perry | Fred Talbot | Al Worthington | 540 | 536 | 4 |
| 1966-09-03 | @ MIN | 139 | W 7-4 | 63-76 | 7 | 24,661 | Mel Stottlemyre | Jim Merritt | Mel Stottlemyre | Jim Merritt | Steve Hamilton | 547 | 540 | 7 |
| 1966-09-04 | @ MIN | 140 | L 2-9 | 63-77 | 7 | 29,244 | Pedro Ramos | Jim Kaat | Jim Kaat | Pedro Ramos | | 549 | 549 | 0 |
| 1966-09-05 | @ BAL | 141 | L 4-5 | 63-79 | 8 | 0 | Fritz Peterson | John Miller | Eddie Fisher | Fritz Peterson | | 553 | 554 | -1 |
| 1966-09-05 | @ BAL | 142 | L 4-7 | 63-79 | 8 | 36,832 | Al Downing | Jim Palmer | Dick Hall | Al Downing | Eddie Fisher | 557 | 561 | -4 |
| 1966-09-06 | @ BAL | 143 | L 1-4 | 63-80 | 8 | 15,540 | Jim Bouton | Dave McNally | Dave McNally | Jim Bouton | | 558 | 565 | -7 |
| 1966-09-07 | @ BAL | 144 | L 2-3 | 63-81 | 10 | 13,703 | Mel Stottlemyre | Wally Bunker | Eddie Fisher | Mel Stottlemyre | Stu Miller | 560 | 568 | -8 |
| 1966-09-09 | @ BOS | 145 | W 2-1 | 64-81 | 8 | 17,398 | Fred Talbot | Bucky Brandon | Fred Talbot | Bucky Brandon | Stan Bahnsen | 562 | 569 | -7 |
| 1966-09-10 | @ BOS | 146 | W 5-1 | 65-81 | 8 | 21,018 | Al Downing | Jose Santiago | Al Downing | Jose Santiago | Mel Stottlemyre | 567 | 570 | -3 |
| 1966-09-11 | @ BOS | 147 | W 4-2 | 66-81 | 8 | 15,482 | Jim Bouton | Lee Stange | Dooley Womack | John Wyatt | | 571 | 572 | -1 |
| 1966-09-13 | vs WS2 | 148 | L 2-3 | 66-82 | 8 | 6,202 | Fritz Peterson | Phil Ortega | Phil Ortega | Fritz Peterson | | 573 | 575 | -2 |
| 1966-09-15 | vs WS2 | 149 | L 4-5 | 67-83 | 8 | 0 | Mel Stottlemyre | Pete Richert | Pete Richert | Mel Stottlemyre | Ron Kline | 577 | 580 | -3 |
| 1966-09-15 | vs WS2 | 150 | W 10-5 | 67-83 | 8 | 3,456 | Stan Bahnsen | Mike McCormick | Stan Bahnsen | Mike McCormick | | 587 | 585 | 2 |
| 1966-09-16 | vs MIN | 151 | L 1-2 | 67-84 | 9 | 9,306 | Jim Bouton | Jim Merritt | Jim Merritt | Jim Bouton | Al Worthington | 588 | 587 | 1 |
| 1966-09-17 | vs MIN | 152 | L 2-4 | 67-85 | 9 | 21,135 | Al Downing | Jim Kaat | Jim Kaat | Al Downing | | 590 | 591 | -1 |
| 1966-09-18 | vs MIN | 153 | L 3-5 | 67-86 | 9 | 12,315 | Fritz Peterson | Jim Ollom | Pete Cimino | Hal Reniff | | 593 | 596 | -3 |
| 1966-09-22 | vs CHA | 154 | L 1-4 | 67-87 | 10 | 413 | Stan Bahnsen | Joe Horlen | Joe Horlen | Stan Bahnsen | Hoyt Wilhelm | 594 | 600 | -6 |
| 1966-09-23 | vs BOS | 155 | L 1-2 | 67-88 | 10 | 1,440 | Mel Stottlemyre | Lee Stange | Lee Stange | Mel Stottlemyre | | 595 | 602 | -7 |
| 1966-09-24 | vs BOS | 156 | W 1-0 | 68-88 | 10 | 5,897 | Fritz Peterson | Jim Lonborg | Fritz Peterson | Jim Lonborg | | 596 | 602 | -6 |
| 1966-09-25 | vs BOS | 157 | W 3-1 | 69-88 | 10 | 16,467 | Jim Bouton | Hank Fischer | Jim Bouton | Hank Fischer | Hal Reniff | 599 | 603 | -4 |
| 1966-09-30 | @ CHA | 158 | L 5-6 | 69-89 | 10 | 11,949 | Stan Bahnsen | Fred Klages | John Buzhardt | Mel Stottlemyre | | 604 | 609 | -5 |
| 1966-10-01 | @ CHA | 159 | W 5-3 | 70-89 | 10 | 5,537 | Fritz Peterson | Joe Horlen | Dooley Womack | Joe Horlen | Jim Bouton | 609 | 612 | -3 |
| 1966-10-02 | @ CHA | 160 | W 2-0 | 71-89 | 10 | 7,832 | Al Downing | Greg Bollo | Al Downing | Greg Bollo | Dooley Womack | 611 | 612 | -1 |