| 1998-03-31 | vs SFN | 1 | L 4-9 | - | | 43,776 | Shane Reynolds | Shawn Estes | John Johnstone | C.J. Nitkowski | | 4 | 9 | -5 |
| 1998-04-01 | vs SFN | 2 | W 7-6 | - | | 13,719 | Mike Hampton | Orel Hershiser | Trever Miller | Julian Tavarez | Billy Wagner | 11 | 15 | -4 |
| 1998-04-02 | vs SFN | 3 | L 2-9 | - | | 15,040 | John Halama | Kirk Rueter | Kirk Rueter | John Halama | | 13 | 24 | -11 |
| 1998-04-03 | vs COL | 4 | W 15-2 | - | | 26,026 | Jose Lima | Jamey Wright | Jose Lima | Jamey Wright | | 28 | 26 | 2 |
| 1998-04-04 | vs COL | 5 | L 3-5 | - | | 21,325 | Sean Bergman | Mark Thompson | Mark Thompson | Sean Bergman | Jerry DiPoto | 31 | 31 | 0 |
| 1998-04-05 | vs COL | 6 | W 6-2 | - | | 21,037 | Shane Reynolds | Darryl Kile | Shane Reynolds | Darryl Kile | | 37 | 33 | 4 |
| 1998-04-06 | vs COL | 7 | W 13-4 | - | | 13,553 | Mike Hampton | John Thomson | Mike Hampton | John Thomson | | 50 | 37 | 13 |
| 1998-04-07 | @ SFN | 8 | L 4-5 | - | | 55,370 | John Halama | Orel Hershiser | Robb Nen | Billy Wagner | | 54 | 42 | 12 |
| 1998-04-08 | @ SFN | 9 | W 6-3 | - | | 10,021 | Jose Lima | Kirk Rueter | Jose Lima | Kirk Rueter | Billy Wagner | 60 | 45 | 15 |
| 1998-04-09 | @ SFN | 10 | W 3-1 | - | | 10,153 | Sean Bergman | Mark Gardner | Sean Bergman | Mark Gardner | C.J. Nitkowski | 63 | 46 | 17 |
| 1998-04-10 | @ LAN | 11 | L 2-7 | - | | 34,994 | Shane Reynolds | Ramon Martinez | Ramon Martinez | Shane Reynolds | | 65 | 53 | 12 |
| 1998-04-11 | @ LAN | 12 | W 6-2 | - | | 40,037 | Mike Hampton | Darren Dreifort | Mike Hampton | Darren Dreifort | Doug Henry | 71 | 55 | 16 |
| 1998-04-12 | @ LAN | 13 | L 6-7 | - | | 33,429 | John Halama | Chan Ho Park | Antonio Osuna | Billy Wagner | | 77 | 62 | 15 |
| 1998-04-13 | @ LAN | 14 | L 1-3 | - | | 32,289 | Jose Lima | Hideo Nomo | Hideo Nomo | Jose Lima | Scott Radinsky | 78 | 65 | 13 |
| 1998-04-15 | @ CIN | 15 | L 1-4 | - | | 15,619 | Shane Reynolds | Brett Tomko | Brett Tomko | Shane Reynolds | Jeff Shaw | 79 | 69 | 10 |
| 1998-04-16 | @ CIN | 16 | W 7-4 | - | | 14,596 | Mike Hampton | David Weathers | Mike Hampton | David Weathers | Billy Wagner | 86 | 73 | 13 |
| 1998-04-17 | vs MON | 17 | W 5-3 | - | | 26,485 | John Halama | Dustin Hermanson | John Halama | Dustin Hermanson | Billy Wagner | 91 | 76 | 15 |
| 1998-04-18 | vs MON | 18 | W 4-3 | - | | 29,362 | Jose Lima | Marc Valdes | Doug Henry | Miguel Batista | | 95 | 79 | 16 |
| 1998-04-19 | vs MON | 19 | L 4-5 | - | | 18,484 | Shane Reynolds | Javier Vazquez | Anthony Telford | Mike Magnante | Ugueth Urbina | 99 | 84 | 15 |
| 1998-04-21 | @ NYN | 20 | W 6-0 | - | | 14,774 | Mike Hampton | Rick Reed | Mike Hampton | Rick Reed | | 105 | 84 | 21 |
| 1998-04-22 | @ NYN | 21 | L 7-10 | - | | 12,772 | John Halama | Dave Mlicki | Dennis Cook | Doug Henry | | 112 | 94 | 18 |
| 1998-04-24 | @ MON | 22 | W 8-4 | - | | 8,713 | Jose Lima | Marc Valdes | Jose Lima | Marc Valdes | | 120 | 98 | 22 |
| 1998-04-25 | @ MON | 23 | W 4-3 | - | | 8,489 | Shane Reynolds | Javier Vazquez | Mike Magnante | Ugueth Urbina | Billy Wagner | 124 | 101 | 23 |
| 1998-04-26 | @ MON | 24 | W 15-0 | - | | 9,889 | Sean Bergman | Trey Moore | Sean Bergman | Trey Moore | Trever Miller | 139 | 101 | 38 |
| 1998-04-27 | @ NYN | 25 | W 4-3 | - | | 17,656 | Mike Hampton | Rick Reed | C.J. Nitkowski | John Franco | Billy Wagner | 143 | 104 | 39 |
| 1998-04-28 | vs NYN | 26 | W 4-3 | - | | 14,943 | John Halama | Al Leiter | Mike Magnante | John Hudek | | 147 | 107 | 40 |
| 1998-04-29 | vs NYN | 27 | W 6-1 | - | | 14,448 | Jose Lima | Dave Mlicki | Jose Lima | Dave Mlicki | | 153 | 108 | 45 |
| 1998-05-01 | @ PHI | 28 | W 12-5 | - | | 11,410 | Shane Reynolds | Matt Beech | Shane Reynolds | Matt Beech | | 165 | 113 | 52 |
| 1998-05-02 | @ PHI | 29 | W 4-1 | - | | 18,766 | Mike Hampton | Curt Schilling | Mike Hampton | Curt Schilling | Billy Wagner | 169 | 114 | 55 |
| 1998-05-03 | @ PHI | 30 | L 3-5 | - | | 21,288 | Sean Bergman | Tyler Green | Wayne Gomes | Sean Bergman | Mark Leiter | 172 | 119 | 53 |
| 1998-05-05 | @ CHN | 31 | W 10-5 | - | | 21,431 | Jose Lima | Mark Clark | Jose Lima | Mark Clark | C.J. Nitkowski | 182 | 124 | 58 |
| 1998-05-06 | @ CHN | 32 | L 0-2 | - | | 15,758 | Shane Reynolds | Kerry Wood | Kerry Wood | Shane Reynolds | | 182 | 126 | 56 |
| 1998-05-08 | @ MIL | 33 | L 1-4 | - | | 14,711 | Mike Hampton | Jeff Juden | Jeff Juden | Mike Hampton | Doug Jones | 183 | 130 | 53 |
| 1998-05-09 | @ MIL | 34 | W 11-6 | - | | 20,145 | Pete Schourek | Cal Eldred | Pete Schourek | Cal Eldred | | 194 | 136 | 58 |
| 1998-05-10 | @ MIL | 35 | W 7-1 | - | | 19,023 | Jose Lima | Steve Woodard | Jose Lima | Steve Woodard | | 201 | 137 | 64 |
| 1998-05-11 | vs FLO | 36 | W 5-2 | - | | 14,110 | Shane Reynolds | Livan Hernandez | Shane Reynolds | Livan Hernandez | Billy Wagner | 206 | 139 | 67 |
| 1998-05-12 | vs FLO | 37 | W 4-2 | - | | 14,919 | Sean Bergman | Chris Hammond | Sean Bergman | Chris Hammond | Billy Wagner | 210 | 141 | 69 |
| 1998-05-13 | vs PIT | 38 | W 1-0 | - | | 14,239 | Mike Hampton | Jon Lieber | Mike Hampton | Jon Lieber | Billy Wagner | 211 | 141 | 70 |
| 1998-05-14 | vs PIT | 39 | L 2-7 | - | | 16,123 | Pete Schourek | Jose Silva | Jose Silva | Pete Schourek | | 213 | 148 | 65 |
| 1998-05-15 | vs ATL | 40 | L 2-3 | - | | 38,941 | Jose Lima | Denny Neagle | Denny Neagle | Jose Lima | Dennis Martinez | 215 | 151 | 64 |
| 1998-05-16 | vs ATL | 41 | W 3-2 | - | | 51,526 | Shane Reynolds | Greg Maddux | Doug Henry | Kerry Ligtenberg | | 218 | 153 | 65 |
| 1998-05-17 | vs ATL | 42 | W 8-1 | - | | 35,250 | Sean Bergman | John Smoltz | Sean Bergman | John Smoltz | | 226 | 154 | 72 |
| 1998-05-18 | vs ATL | 43 | L 0-4 | - | | 22,119 | Mike Hampton | Tom Glavine | Tom Glavine | Mike Hampton | | 226 | 158 | 68 |
| 1998-05-19 | @ MON | 44 | L 2-4 | - | | 9,126 | Pete Schourek | Carlos Perez | Carlos Perez | Pete Schourek | Ugueth Urbina | 228 | 162 | 66 |
| 1998-05-20 | @ MON | 45 | W 4-3 | - | | 8,372 | Jose Lima | Trey Moore | Doug Henry | Anthony Telford | Billy Wagner | 232 | 165 | 67 |
| 1998-05-21 | @ MON | 46 | W 6-0 | - | | 7,601 | Shane Reynolds | Miguel Batista | Shane Reynolds | Shayne Bennett | | 238 | 165 | 73 |
| 1998-05-22 | vs SDN | 47 | L 6-9 | - | | 28,550 | Sean Bergman | Pete Smith | Dan Miceli | C.J. Nitkowski | Trevor Hoffman | 244 | 174 | 70 |
| 1998-05-23 | vs SDN | 48 | W 4-3 | - | | 36,281 | Mike Hampton | Mark Langston | Trever Miller | Dan Miceli | Billy Wagner | 248 | 177 | 71 |
| 1998-05-24 | vs SDN | 49 | W 5-2 | - | | 25,701 | Pete Schourek | Joey Hamilton | Pete Schourek | Joey Hamilton | Billy Wagner | 253 | 179 | 74 |
| 1998-05-25 | vs LAN | 50 | L 3-4 | - | | 34,079 | Jose Lima | Hideo Nomo | Jim Bruske | Bob Scanlan | Scott Radinsky | 256 | 183 | 73 |
| 1998-05-26 | vs LAN | 51 | W 13-2 | - | | 16,251 | Shane Reynolds | Ismael Valdez | Shane Reynolds | Ismael Valdez | | 269 | 185 | 84 |
| 1998-05-27 | vs LAN | 52 | L 1-3 | - | | 17,190 | Sean Bergman | Darren Dreifort | Darren Dreifort | Sean Bergman | Scott Radinsky | 270 | 188 | 82 |
| 1998-05-29 | @ COL | 53 | W 7-6 | - | | 48,325 | Mike Hampton | Pedro Astacio | Mike Hampton | Pedro Astacio | Billy Wagner | 277 | 194 | 83 |
| 1998-05-30 | @ COL | 54 | L 3-6 | - | | 48,036 | Pete Schourek | John Thomson | John Thomson | Pete Schourek | Jerry DiPoto | 280 | 200 | 80 |
| 1998-05-31 | @ COL | 55 | L 5-7 | - | | 48,097 | Jose Lima | Bobby Jones | Chuck McElroy | Doug Henry | | 285 | 207 | 78 |
| 1998-06-02 | @ SDN | 56 | W 4-3 | - | | 15,735 | Shane Reynolds | Mark Langston | Shane Reynolds | Carlos Reyes | Billy Wagner | 289 | 210 | 79 |
| 1998-06-03 | @ SDN | 57 | W 8-2 | - | | 13,229 | Sean Bergman | Joey Hamilton | Sean Bergman | Joey Hamilton | | 297 | 212 | 85 |
| 1998-06-04 | @ SDN | 58 | L 1-5 | - | | 21,027 | Mike Hampton | Andy Ashby | Andy Ashby | Mike Hampton | | 298 | 217 | 81 |
| 1998-06-05 | vs KCA | 59 | L 0-3 | - | | 27,895 | Pete Schourek | Tim Belcher | Tim Belcher | Pete Schourek | Jeff Montgomery | 298 | 220 | 78 |
| 1998-06-06 | vs KCA | 60 | W 6-0 | - | | 25,516 | Jose Lima | Jose Rosado | Jose Lima | Jose Rosado | | 304 | 220 | 84 |
| 1998-06-07 | vs KCA | 61 | W 7-1 | - | | 23,228 | Shane Reynolds | Jim Pittsley | Shane Reynolds | Jim Pittsley | | 311 | 221 | 90 |
| 1998-06-08 | @ DET | 62 | W 9-5 | - | | 11,767 | Sean Bergman | Seth Greisinger | Doug Henry | Todd Jones | | 320 | 226 | 94 |
| 1998-06-09 | @ DET | 63 | W 5-3 | - | | 10,871 | Mike Hampton | Brian Moehler | Mike Hampton | Todd Jones | Billy Wagner | 325 | 229 | 96 |
| 1998-06-10 | @ DET | 64 | W 10-3 | - | | 11,471 | Pete Schourek | Frank Castillo | Pete Schourek | Frank Castillo | | 335 | 232 | 103 |
| 1998-06-12 | @ CIN | 65 | L 1-8 | - | | 21,310 | Jose Lima | Mike Remlinger | Mike Remlinger | Jose Lima | | 336 | 240 | 96 |
| 1998-06-13 | @ CIN | 66 | L 4-7 | - | | 28,055 | Shane Reynolds | Scott Klingenbeck | Scott Klingenbeck | Shane Reynolds | Jeff Shaw | 340 | 247 | 93 |
| 1998-06-14 | @ CIN | 67 | W 6-3 | - | | 22,008 | Sean Bergman | Scott Winchester | Billy Wagner | Jeff Shaw | | 346 | 250 | 96 |
| 1998-06-15 | @ CIN | 68 | W 13-2 | - | | 14,556 | Mike Hampton | Brett Tomko | Mike Magnante | Brett Tomko | | 359 | 252 | 107 |
| 1998-06-16 | vs SLN | 69 | L 4-9 | - | | 34,822 | Pete Schourek | Juan Acevedo | Juan Acevedo | Pete Schourek | | 363 | 261 | 102 |
| 1998-06-17 | vs SLN | 70 | W 6-5 | - | | 37,147 | Jose Lima | Todd Stottlemyre | C.J. Nitkowski | Jeff Brantley | | 369 | 266 | 103 |
| 1998-06-18 | vs SLN | 71 | L 6-7 | - | | 43,806 | Shane Reynolds | Kent Bottenfield | Kent Bottenfield | Shane Reynolds | Rich Croushore | 375 | 273 | 102 |
| 1998-06-19 | vs CIN | 72 | W 4-2 | - | | 29,251 | Sean Bergman | Scott Winchester | Sean Bergman | Scott Winchester | Billy Wagner | 379 | 275 | 104 |
| 1998-06-20 | vs CIN | 73 | W 9-8 | - | | 24,301 | Scott Elarton | Brett Tomko | C.J. Nitkowski | Rick Krivda | Billy Wagner | 388 | 283 | 105 |
| 1998-06-21 | vs CIN | 74 | W 3-1 | - | | 42,281 | Pete Schourek | Pete Harnisch | Pete Schourek | Pete Harnisch | Mike Magnante | 391 | 284 | 107 |
| 1998-06-22 | vs MIN | 75 | L 3-5 | - | | 23,168 | Jose Lima | Eric Milton | Eric Milton | Jose Lima | Rick Aguilera | 394 | 289 | 105 |
| 1998-06-23 | vs MIN | 76 | W 9-0 | - | | 27,157 | Shane Reynolds | Bob Tewksbury | Shane Reynolds | Bob Tewksbury | | 403 | 289 | 114 |
| 1998-06-24 | @ COL | 77 | L 6-8 | - | | 48,150 | Sean Bergman | Pedro Astacio | Pedro Astacio | Sean Bergman | Dave Veres | 409 | 297 | 112 |
| 1998-06-25 | @ COL | 78 | L 5-6 | - | | 48,046 | Scott Elarton | Mike Saipe | Curt Leskanic | Mike Magnante | | 414 | 303 | 111 |
| 1998-06-26 | @ CLE | 79 | L 2-4 | - | | 43,222 | Pete Schourek | Bartolo Colon | Bartolo Colon | Mike Magnante | Michael Jackson | 416 | 307 | 109 |
| 1998-06-27 | @ CLE | 80 | W 9-5 | - | | 43,132 | Jose Lima | Dwight Gooden | Billy Wagner | Jose Mesa | | 425 | 312 | 113 |
| 1998-06-28 | @ CLE | 81 | W 12-3 | - | | 43,047 | Shane Reynolds | Charles Nagy | Shane Reynolds | Charles Nagy | C.J. Nitkowski | 437 | 315 | 122 |
| 1998-06-30 | vs CHA | 82 | W 17-2 | - | | 26,400 | Sean Bergman | Jaime Navarro | Sean Bergman | Jaime Navarro | | 454 | 317 | 137 |
| 1998-07-01 | vs CHA | 83 | W 10-4 | - | | 29,050 | Pete Schourek | Jim Parque | Pete Schourek | Jim Parque | | 464 | 321 | 143 |
| 1998-07-02 | vs CHA | 84 | L 3-4 | - | | 25,344 | Jose Lima | James Baldwin | James Baldwin | Jose Lima | Bill Simas | 467 | 325 | 142 |
| 1998-07-03 | vs ARI | 85 | W 6-5 | - | | 34,382 | Shane Reynolds | Andy Benes | Shane Reynolds | Andy Benes | Billy Wagner | 473 | 330 | 143 |
| 1998-07-04 | vs ARI | 86 | L 4-7 | - | | 31,477 | Mike Hampton | Brian Anderson | Brian Anderson | Mike Hampton | | 477 | 337 | 140 |
| 1998-07-05 | vs ARI | 87 | W 5-2 | - | | 23,607 | Sean Bergman | Willie Blair | Sean Bergman | Willie Blair | Billy Wagner | 482 | 339 | 143 |
| 1998-07-09 | @ SLN | 88 | W 5-4 | - | | 34,398 | Shane Reynolds | Todd Stottlemyre | Shane Reynolds | Todd Stottlemyre | Billy Wagner | 487 | 343 | 144 |
| 1998-07-10 | @ SLN | 89 | L 3-6 | - | | 44,655 | Mike Hampton | Matt Morris | Curtis King | C.J. Nitkowski | Jeff Brantley | 490 | 349 | 141 |
| 1998-07-11 | @ SLN | 90 | L 3-4 | - | | 45,760 | Jose Lima | Kent Mercker | Lance Painter | Billy Wagner | | 493 | 353 | 140 |
| 1998-07-12 | @ SLN | 91 | L 4-6 | - | | 45,485 | Sean Bergman | Juan Acevedo | Juan Acevedo | Sean Bergman | Rich Croushore | 497 | 359 | 138 |
| 1998-07-13 | @ ARI | 92 | L 3-5 | - | | 40,007 | Pete Schourek | Amaury Telemaco | Amaury Telemaco | Pete Schourek | Gregg Olson | 500 | 364 | 136 |
| 1998-07-14 | @ ARI | 93 | W 4-2 | - | | 40,419 | Shane Reynolds | Omar Daal | Shane Reynolds | Omar Daal | Billy Wagner | 504 | 366 | 138 |
| 1998-07-15 | @ ARI | 94 | L 8-9 | - | | 42,229 | Mike Hampton | Andy Benes | Alan Embree | Mike Magnante | | 512 | 375 | 137 |
| 1998-07-17 | vs SFN | 95 | W 10-7 | - | | 40,709 | Jose Lima | Kirk Rueter | Jose Lima | Kirk Rueter | | 522 | 382 | 140 |
| 1998-07-18 | vs SFN | 96 | W 7-2 | - | | 35,257 | Sean Bergman | Danny Darwin | Sean Bergman | Danny Darwin | | 529 | 384 | 145 |
| 1998-07-19 | vs SFN | 97 | W 4-3 | - | | 32,900 | Pete Schourek | Mark Gardner | Doug Henry | Robb Nen | | 533 | 387 | 146 |
| 1998-07-20 | vs COL | 98 | W 10-9 | - | | 25,491 | Shane Reynolds | Jamey Wright | Doug Henry | Dave Veres | | 543 | 396 | 147 |
| 1998-07-21 | vs COL | 99 | L 0-5 | - | | 28,718 | Mike Hampton | Mark Brownson | Mark Brownson | Mike Hampton | | 543 | 401 | 142 |
| 1998-07-22 | @ LAN | 100 | L 4-6 | - | | 31,365 | Jose Lima | Brian Bohanon | Brian Bohanon | Jose Lima | Jeff Shaw | 547 | 407 | 140 |
| 1998-07-23 | @ LAN | 101 | W 8-6 | - | | 40,205 | Sean Bergman | Dave Mlicki | Doug Henry | Darren Hall | Jay Powell | 555 | 413 | 142 |
| 1998-07-24 | @ SDN | 102 | W 2-1 | - | | 31,047 | Pete Schourek | Sterling Hitchcock | Pete Schourek | Sterling Hitchcock | Mike Magnante | 557 | 414 | 143 |
| 1998-07-25 | @ SDN | 103 | L 5-6 | - | | 54,176 | Shane Reynolds | Mark Langston | Mark Langston | Shane Reynolds | Trevor Hoffman | 562 | 420 | 142 |
| 1998-07-26 | @ SDN | 104 | L 4-5 | - | | 41,034 | Mike Hampton | Kevin Brown | Donne Wall | Mike Magnante | | 566 | 425 | 141 |
| 1998-07-27 | vs FLO | 105 | W 9-1 | - | | 20,888 | Jose Lima | Brian Meadows | Jose Lima | Brian Meadows | | 575 | 426 | 149 |
| 1998-07-28 | vs FLO | 106 | W 7-3 | - | | 26,220 | Sean Bergman | Kirt Ojala | Sean Bergman | Kirt Ojala | | 582 | 429 | 153 |
| 1998-07-29 | vs FLO | 107 | W 10-6 | - | | 21,870 | Pete Schourek | Andy Larkin | Pete Schourek | Andy Larkin | Scott Elarton | 592 | 435 | 157 |
| 1998-07-30 | vs FLO | 108 | L 3-4 | - | | 33,303 | Shane Reynolds | Livan Hernandez | Livan Hernandez | Shane Reynolds | | 595 | 439 | 156 |
| 1998-07-31 | @ PIT | 109 | W 7-4 | - | | 32,476 | Mike Hampton | Francisco Cordova | Mike Hampton | Francisco Cordova | Doug Henry | 602 | 443 | 159 |
| 1998-08-01 | @ PIT | 110 | W 2-1 | - | | 19,783 | Jose Lima | Jason Schmidt | Jose Lima | Mike Williams | | 604 | 444 | 160 |
| 1998-08-02 | @ PIT | 111 | W 6-2 | - | | 21,201 | Randy Johnson | Todd Van Poppel | Randy Johnson | Jason Christiansen | Scott Elarton | 610 | 446 | 164 |
| 1998-08-03 | @ FLO | 112 | L 3-11 | - | | 14,484 | Sean Bergman | Andy Larkin | Andy Larkin | Sean Bergman | Matt Mantei | 613 | 457 | 156 |
| 1998-08-04 | @ FLO | 113 | W 9-5 | - | | 14,586 | Shane Reynolds | Livan Hernandez | Shane Reynolds | Livan Hernandez | | 622 | 462 | 160 |
| 1998-08-05 | @ FLO | 114 | L 3-5 | - | | 19,038 | Mike Hampton | Jesus Sanchez | Jesus Sanchez | Mike Hampton | Matt Mantei | 625 | 467 | 158 |
| 1998-08-07 | vs PHI | 115 | W 9-0 | - | | 52,071 | Randy Johnson | Mike Welch | Randy Johnson | Mike Welch | | 634 | 467 | 167 |
| 1998-08-08 | vs PHI | 116 | W 7-6 | - | | 42,523 | Jose Lima | Carlton Loewer | Doug Henry | Mark Leiter | | 641 | 473 | 168 |
| 1998-08-09 | vs PHI | 117 | W 11-2 | - | | 28,651 | Shane Reynolds | Matt Beech | Shane Reynolds | Matt Beech | | 652 | 475 | 177 |
| 1998-08-10 | vs MIL | 118 | W 5-2 | - | | 18,995 | Mike Hampton | Bill Pulsipher | Scott Elarton | Chad Fox | Billy Wagner | 657 | 477 | 180 |
| 1998-08-11 | vs MIL | 119 | W 6-5 | - | | 20,553 | Sean Bergman | Bronswell Patrick | Mike Magnante | Eric Plunk | | 663 | 482 | 181 |
| 1998-08-12 | vs MIL | 120 | W 3-0 | - | | 40,217 | Randy Johnson | Brad Woodall | Randy Johnson | Brad Woodall | | 666 | 482 | 184 |
| 1998-08-13 | vs MIL | 121 | W 6-2 | - | | 21,218 | Jose Lima | Steve Woodard | Jose Lima | Steve Woodard | | 672 | 484 | 188 |
| 1998-08-14 | vs CHN | 122 | L 4-6 | - | | 45,040 | Shane Reynolds | Mark Clark | Mark Clark | Shane Reynolds | Rod Beck | 676 | 490 | 186 |
| 1998-08-15 | vs CHN | 123 | W 5-4 | - | | 52,003 | Mike Hampton | Kevin Tapani | Billy Wagner | Terry Mulholland | | 681 | 494 | 187 |
| 1998-08-16 | vs CHN | 124 | L 1-2 | - | | 52,199 | Sean Bergman | Kerry Wood | Matt Karchner | Jay Powell | Rod Beck | 682 | 496 | 186 |
| 1998-08-17 | @ PHI | 125 | L 0-4 | - | | 18,975 | Randy Johnson | Paul Byrd | Paul Byrd | Randy Johnson | | 682 | 500 | 182 |
| 1998-08-18 | @ PHI | 126 | W 8-2 | - | | 17,541 | Jose Lima | Mike Grace | Jose Lima | Mike Grace | | 690 | 502 | 188 |
| 1998-08-19 | @ PHI | 127 | W 4-3 | - | | 21,341 | Shane Reynolds | Carlton Loewer | Shane Reynolds | Mark Leiter | Billy Wagner | 694 | 505 | 189 |
| 1998-08-20 | @ MIL | 128 | L 5-6 | - | | 17,589 | Mike Hampton | Scott Karl | Bob Wickman | Mike Magnante | | 699 | 511 | 188 |
| 1998-08-21 | @ MIL | 129 | W 5-2 | - | | 26,820 | Sean Bergman | Bill Pulsipher | Sean Bergman | Bill Pulsipher | Jay Powell | 704 | 513 | 191 |
| 1998-08-22 | @ CHN | 130 | W 8-3 | - | | 39,886 | Randy Johnson | Don Wengert | Randy Johnson | Don Wengert | | 712 | 516 | 196 |
| 1998-08-23 | @ CHN | 131 | W 13-3 | - | | 38,714 | Jose Lima | Steve Trachsel | Jose Lima | Steve Trachsel | | 725 | 519 | 206 |
| 1998-08-24 | @ CHN | 132 | W 12-3 | - | | 34,711 | Shane Reynolds | Mark Clark | Shane Reynolds | Mark Clark | | 737 | 522 | 215 |
| 1998-08-25 | vs ATL | 133 | W 3-2 | - | | 32,157 | Mike Hampton | Kevin Millwood | Mike Hampton | Kevin Millwood | Billy Wagner | 740 | 524 | 216 |
| 1998-08-26 | vs ATL | 134 | L 2-6 | - | | 32,651 | Sean Bergman | John Smoltz | John Smoltz | Sean Bergman | | 742 | 530 | 212 |
| 1998-08-28 | vs PIT | 135 | W 2-0 | - | | 40,709 | Randy Johnson | Francisco Cordova | Randy Johnson | Francisco Cordova | | 744 | 530 | 214 |
| 1998-08-29 | vs PIT | 136 | W 6-3 | - | | 41,762 | Jose Lima | Jason Schmidt | Jose Lima | Jason Schmidt | Jay Powell | 750 | 533 | 217 |
| 1998-08-30 | vs PIT | 137 | W 11-4 | - | | 25,342 | Shane Reynolds | Sean Lawrence | Shane Reynolds | Jeff McCurry | | 761 | 537 | 224 |
| 1998-08-31 | @ ATL | 138 | W 4-3 | - | | 33,883 | Mike Hampton | John Smoltz | Jay Powell | John Smoltz | Billy Wagner | 765 | 540 | 225 |
| 1998-09-01 | @ ATL | 139 | L 4-6 | - | | 31,168 | Sean Bergman | Denny Neagle | Denny Neagle | Scott Elarton | Kerry Ligtenberg | 769 | 546 | 223 |
| 1998-09-02 | @ ATL | 140 | W 4-2 | - | | 46,238 | Randy Johnson | Greg Maddux | Randy Johnson | Greg Maddux | Billy Wagner | 773 | 548 | 225 |
| 1998-09-04 | @ ARI | 141 | L 1-3 | - | | 41,396 | Jose Lima | Amaury Telemaco | Amaury Telemaco | Jose Lima | Gregg Olson | 774 | 551 | 223 |
| 1998-09-05 | @ ARI | 142 | W 6-5 | - | | 43,638 | Shane Reynolds | Clint Sodowsky | Billy Wagner | Alan Embree | | 780 | 556 | 224 |
| 1998-09-06 | @ ARI | 143 | W 10-1 | - | | 44,076 | Mike Hampton | Omar Daal | Mike Hampton | Omar Daal | | 790 | 557 | 233 |
| 1998-09-07 | vs CIN | 144 | W 1-0 | - | | 42,787 | Randy Johnson | Steve Parris | Randy Johnson | Steve Parris | | 791 | 557 | 234 |
| 1998-09-08 | vs CIN | 145 | W 13-7 | - | | 16,574 | Sean Bergman | Jason Bere | Sean Bergman | Jason Bere | | 804 | 564 | 240 |
| 1998-09-09 | vs MIL | 146 | W 6-2 | - | | 24,462 | Jose Lima | Steve Woodard | Jose Lima | Steve Woodard | Billy Wagner | 810 | 566 | 244 |
| 1998-09-10 | vs MIL | 147 | W 7-1 | - | | 20,813 | Shane Reynolds | Scott Karl | Shane Reynolds | Scott Karl | | 817 | 567 | 250 |
| 1998-09-11 | vs SLN | 148 | W 8-2 | - | | 52,186 | Mike Hampton | Matt Morris | Jay Powell | Matt Morris | | 825 | 569 | 256 |
| 1998-09-12 | vs SLN | 149 | W 3-2 | - | | 52,493 | Randy Johnson | Darren Oliver | Randy Johnson | Darren Oliver | Billy Wagner | 828 | 571 | 257 |
| 1998-09-13 | vs SLN | 150 | L 2-3 | - | | 52,338 | Sean Bergman | Kent Mercker | Kent Mercker | Sean Bergman | Juan Acevedo | 830 | 574 | 256 |
| 1998-09-14 | vs NYN | 151 | L 4-7 | - | | 24,241 | Jose Lima | Masato Yoshii | Greg McMichael | Mike Magnante | John Franco | 834 | 581 | 253 |
| 1998-09-15 | vs NYN | 152 | W 6-5 | - | | 0 | Shane Reynolds | Armando Reynoso | Jay Powell | Jeff Tam | | 840 | 586 | 254 |
| 1998-09-15 | vs NYN | 153 | L 4-8 | - | | 40,835 | Trever Miller | Al Leiter | Al Leiter | Jay Powell | Turk Wendell | 844 | 594 | 250 |
| 1998-09-16 | vs NYN | 154 | L 3-4 | - | | 24,269 | Mike Hampton | Bobby Jones | Greg McMichael | Sean Bergman | Turk Wendell | 847 | 598 | 249 |
| 1998-09-18 | @ PIT | 155 | W 5-2 | - | | 16,937 | Randy Johnson | Elmer Dessens | Randy Johnson | Elmer Dessens | Jay Powell | 852 | 600 | 252 |
| 1998-09-19 | @ PIT | 156 | L 1-7 | - | | 20,670 | Jose Lima | Francisco Cordova | Francisco Cordova | Jose Lima | | 853 | 607 | 246 |
| 1998-09-20 | @ PIT | 157 | W 2-0 | - | | 23,657 | Shane Reynolds | Jason Schmidt | Shane Reynolds | Jason Schmidt | Billy Wagner | 855 | 607 | 248 |
| 1998-09-22 | @ SLN | 158 | L 0-4 | - | | 40,739 | Mike Hampton | Matt Morris | Matt Morris | Mike Hampton | | 855 | 611 | 244 |
| 1998-09-23 | @ SLN | 159 | W 7-1 | - | | 38,997 | Randy Johnson | Darren Oliver | Randy Johnson | Darren Oliver | | 862 | 612 | 250 |
| 1998-09-25 | vs CHN | 160 | W 6-2 | - | | 51,831 | Jose Lima | Kevin Tapani | Jose Lima | Kevin Tapani | | 868 | 614 | 254 |
| 1998-09-26 | vs CHN | 161 | L 2-3 | - | | 51,950 | Shane Reynolds | Mark Clark | Mark Clark | Jay Powell | Rod Beck | 870 | 617 | 253 |
| 1998-09-27 | vs CHN | 162 | W 4-3 | - | | 51,916 | Mike Hampton | Terry Mulholland | Scott Elarton | Rod Beck | | 874 | 620 | 254 |