| 2004-04-05 | vs SDN | 1 | L 2-8 | 0-1 | 5 | 53,850 | Hideo Nomo | Brian Lawrence | Brian Lawrence | Hideo Nomo | | 2 | 8 | -6 |
| 2004-04-06 | vs SDN | 2 | W 5-4 | 1-1 | 3 | 26,437 | Odalis Perez | Jake Peavy | Eric Gagne | Akinori Otsuka | | 7 | 12 | -5 |
| 2004-04-07 | vs SDN | 3 | W 2-1 | 2-1 | 1 | 26,932 | Jeff Weaver | Adam Eaton | Jose Lima | Eddie Oropesa | | 9 | 13 | -4 |
| 2004-04-09 | vs COL | 4 | W 5-1 | 3-1 | 1 | 54,599 | Kazuhisa Ishii | Scott Elarton | Kazuhisa Ishii | Scott Elarton | Wilson Alvarez | 14 | 14 | 0 |
| 2004-04-10 | vs COL | 5 | W 7-4 | 4-1 | 1 | 35,318 | Hideo Nomo | Denny Stark | Hideo Nomo | Denny Stark | Eric Gagne | 21 | 18 | 3 |
| 2004-04-11 | vs COL | 6 | L 2-4 | 4-2 | 1 | 27,076 | Odalis Perez | Shawn Estes | Shawn Estes | Odalis Perez | Shawn Chacon | 23 | 22 | 1 |
| 2004-04-13 | @ SDN | 7 | L 3-8 | 4-3 | 2 | 35,156 | Jeff Weaver | Adam Eaton | Adam Eaton | Jeff Weaver | | 26 | 30 | -4 |
| 2004-04-14 | @ SDN | 8 | W 11-4 | 5-3 | 1 | 34,558 | Kazuhisa Ishii | David Wells | Kazuhisa Ishii | David Wells | | 37 | 34 | 3 |
| 2004-04-15 | @ SDN | 9 | W 7-5 | 6-3 | 1 | 40,104 | Hideo Nomo | Brian Lawrence | Hideo Nomo | Brian Lawrence | Eric Gagne | 44 | 39 | 5 |
| 2004-04-16 | @ SFN | 10 | W 3-2 | 7-3 | 1 | 42,662 | Odalis Perez | Jason Schmidt | Odalis Perez | Jason Schmidt | Eric Gagne | 47 | 41 | 6 |
| 2004-04-17 | @ SFN | 11 | W 5-4 | 8-3 | 1 | 42,663 | Jose Lima | Kirk Rueter | Jose Lima | Kirk Rueter | Eric Gagne | 52 | 45 | 7 |
| 2004-04-18 | @ SFN | 12 | W 7-6 | 9-3 | 1 | 42,377 | Jeff Weaver | Brett Tomko | Jeff Weaver | Brett Tomko | Eric Gagne | 59 | 51 | 8 |
| 2004-04-20 | @ COL | 13 | L 1-7 | 9-4 | 1 | 22,169 | Kazuhisa Ishii | Joe Kennedy | Joe Kennedy | Kazuhisa Ishii | | 60 | 58 | 2 |
| 2004-04-21 | @ COL | 14 | W 9-4 | 10-4 | 1 | 21,685 | Hideo Nomo | Scott Elarton | Hideo Nomo | Scott Elarton | | 69 | 62 | 7 |
| 2004-04-22 | @ COL | 15 | L 1-7 | 10-5 | 1 | 19,667 | Jose Lima | Shawn Estes | Shawn Estes | Jose Lima | | 70 | 69 | 1 |
| 2004-04-23 | vs SFN | 16 | W 5-4 | 11-5 | 1 | 54,598 | Odalis Perez | Brett Tomko | Darren Dreifort | Matt Herges | | 75 | 73 | 2 |
| 2004-04-24 | vs SFN | 17 | L 3-5 | 11-6 | 1 | 54,820 | Jeff Weaver | Jerome Williams | Jerome Williams | Jeff Weaver | Matt Herges | 78 | 78 | 0 |
| 2004-04-25 | vs SFN | 18 | W 9-0 | 12-6 | 1 | 54,235 | Kazuhisa Ishii | Brian Cooper | Kazuhisa Ishii | Brian Cooper | | 87 | 78 | 9 |
| 2004-04-27 | vs NYN | 19 | L 5-9 | 12-7 | 1 | 28,524 | Hideo Nomo | Tom Glavine | Tom Glavine | Hideo Nomo | | 92 | 87 | 5 |
| 2004-04-28 | vs NYN | 20 | W 3-2 | 13-7 | 1 | 29,319 | Odalis Perez | Steve Trachsel | Odalis Perez | Steve Trachsel | Eric Gagne | 95 | 89 | 6 |
| 2004-04-29 | vs NYN | 21 | L 1-6 | 13-8 | 1 | 32,067 | Jeff Weaver | Jae Weong Seo | Jae Weong Seo | Jeff Weaver | | 96 | 95 | 1 |
| 2004-04-30 | vs MON | 22 | W 13-4 | 14-8 | 1 | 54,958 | Kazuhisa Ishii | Zach Day | Kazuhisa Ishii | Zach Day | | 109 | 99 | 10 |
| 2004-05-01 | vs MON | 23 | W 5-4 | 15-8 | 1 | 52,900 | Jose Lima | Livan Hernandez | Guillermo Mota | Luis Ayala | Eric Gagne | 114 | 103 | 11 |
| 2004-05-02 | vs MON | 24 | L 4-6 | 15-9 | 1 | 35,351 | Hideo Nomo | Sun-Woo Kim | Sun-Woo Kim | Hideo Nomo | | 118 | 109 | 9 |
| 2004-05-04 | @ FLO | 25 | W 4-3 | 16-9 | 1 | 12,520 | Odalis Perez | Josh Beckett | Duaner Sanchez | Justin Wayne | Eric Gagne | 122 | 112 | 10 |
| 2004-05-05 | @ FLO | 26 | L 0-2 | 16-10 | 1 | 13,308 | Jeff Weaver | Brad Penny | Brad Penny | Jeff Weaver | Armando Benitez | 122 | 114 | 8 |
| 2004-05-06 | @ FLO | 27 | W 9-4 | 17-10 | 1 | 16,109 | Kazuhisa Ishii | Dontrelle Willis | Kazuhisa Ishii | Dontrelle Willis | Eric Gagne | 131 | 118 | 13 |
| 2004-05-07 | @ PIT | 28 | W 4-0 | 18-10 | 1 | 20,944 | Wilson Alvarez | Oliver Perez | Wilson Alvarez | Oliver Perez | | 135 | 118 | 17 |
| 2004-05-08 | @ PIT | 29 | W 4-3 | 19-10 | 1 | 26,610 | Hideo Nomo | Ryan Vogelsong | Guillermo Mota | Salomon Torres | Eric Gagne | 139 | 121 | 18 |
| 2004-05-09 | @ PIT | 30 | W 9-7 | 20-10 | 1 | 16,554 | Odalis Perez | Josh Fogg | Brian Falkenborg | John Grabow | | 148 | 128 | 20 |
| 2004-05-11 | vs CHN | 31 | W 7-3 | 21-10 | 1 | 35,439 | Jeff Weaver | Kerry Wood | Jeff Weaver | Kerry Wood | | 155 | 131 | 24 |
| 2004-05-12 | vs CHN | 32 | W 4-0 | 22-10 | 1 | 43,233 | Wilson Alvarez | Matt Clement | Wilson Alvarez | Matt Clement | | 159 | 131 | 28 |
| 2004-05-13 | vs CHN | 33 | L 3-7 | 22-11 | 1 | 39,591 | Hideo Nomo | Carlos Zambrano | Carlos Zambrano | Hideo Nomo | LaTroy Hawkins | 162 | 138 | 24 |
| 2004-05-14 | vs CIN | 34 | L 1-2 | 22-12 | 1 | 53,647 | Kazuhisa Ishii | Paul Wilson | Paul Wilson | Kazuhisa Ishii | Danny Graves | 163 | 140 | 23 |
| 2004-05-15 | vs CIN | 35 | L 0-4 | 22-13 | 1 | 48,787 | Odalis Perez | Todd Van Poppel | Todd Van Poppel | Odalis Perez | Danny Graves | 163 | 144 | 19 |
| 2004-05-16 | vs CIN | 36 | L 3-6 | 22-14 | 1 | 41,479 | Jeff Weaver | Aaron Harang | Aaron Harang | Jeff Weaver | Danny Graves | 166 | 150 | 16 |
| 2004-05-18 | @ PHI | 37 | L 7-8 | 22-15 | 1 | 36,073 | Wilson Alvarez | Vicente Padilla | Vicente Padilla | Guillermo Mota | Tim Worrell | 173 | 158 | 15 |
| 2004-05-19 | @ PHI | 38 | L 4-9 | 22-16 | 1 | 33,916 | Hideo Nomo | Eric Milton | Eric Milton | Hideo Nomo | | 177 | 167 | 10 |
| 2004-05-20 | @ PHI | 39 | L 0-4 | 22-17 | 1 | 37,793 | Kazuhisa Ishii | Brett Myers | Brett Myers | Kazuhisa Ishii | | 177 | 171 | 6 |
| 2004-05-21 | @ ATL | 40 | L 0-2 | 22-18 | 1 | 27,194 | Odalis Perez | Russ Ortiz | Russ Ortiz | Odalis Perez | John Smoltz | 177 | 173 | 4 |
| 2004-05-22 | @ ATL | 41 | W 7-4 | 23-18 | 1 | 31,850 | Jeff Weaver | Jaret Wright | Jeff Weaver | Jaret Wright | | 184 | 177 | 7 |
| 2004-05-23 | @ ATL | 42 | L 1-5 | 23-19 | 1 | 29,738 | Wilson Alvarez | Mike Hampton | Mike Hampton | Wilson Alvarez | | 185 | 182 | 3 |
| 2004-05-25 | @ MIL | 43 | W 5-3 | 24-19 | 1 | 16,129 | Kazuhisa Ishii | Victor Santos | Jose Lima | Victor Santos | Eric Gagne | 190 | 185 | 5 |
| 2004-05-26 | @ MIL | 44 | L 1-2 | 24-20 | 1 | 14,084 | Odalis Perez | Chris Capuano | Matt Kinney | Duaner Sanchez | | 191 | 187 | 4 |
| 2004-05-27 | @ MIL | 45 | L 1-3 | 24-21 | 2 | 24,616 | Jeff Weaver | Ben Sheets | Ben Sheets | Jeff Weaver | Danny Kolb | 192 | 190 | 2 |
| 2004-05-28 | vs ARI | 46 | L 3-6 | 24-22 | 2 | 46,455 | Wilson Alvarez | Randy Johnson | Randy Johnson | Wilson Alvarez | Elmer Dessens | 195 | 196 | -1 |
| 2004-05-29 | vs ARI | 47 | W 10-0 | 25-22 | 2 | 35,343 | Jose Lima | Brandon Webb | Jose Lima | Brandon Webb | | 205 | 196 | 9 |
| 2004-05-30 | vs ARI | 48 | W 3-0 | 26-22 | 2 | 41,060 | Kazuhisa Ishii | Casey Fossum | Kazuhisa Ishii | Casey Fossum | Eric Gagne | 208 | 196 | 12 |
| 2004-05-31 | vs MIL | 49 | W 3-2 | 27-22 | 1 | 32,642 | Odalis Perez | Matt Wise | Eric Gagne | Dave Burba | | 211 | 198 | 13 |
| 2004-06-01 | vs MIL | 50 | L 1-4 | 27-23 | 1 | 22,402 | Jeff Weaver | Doug Davis | Doug Davis | Jeff Weaver | Danny Kolb | 212 | 202 | 10 |
| 2004-06-02 | vs MIL | 51 | W 5-2 | 28-23 | 1 | 27,871 | Edwin Jackson | Ben Hendrickson | Edwin Jackson | Ben Hendrickson | Eric Gagne | 217 | 204 | 13 |
| 2004-06-04 | @ ARI | 52 | W 7-3 | 29-23 | 1 | 32,182 | Kazuhisa Ishii | Casey Fossum | Kazuhisa Ishii | Casey Fossum | Guillermo Mota | 224 | 207 | 17 |
| 2004-06-05 | @ ARI | 53 | W 10-3 | 30-23 | 1 | 42,407 | Odalis Perez | Edgar Gonzalez | Odalis Perez | Edgar Gonzalez | | 234 | 210 | 24 |
| 2004-06-06 | @ ARI | 54 | L 5-6 | 30-24 | 1 | 34,059 | Jeff Weaver | Steve Sparks | Scott Service | Darren Dreifort | Jose Valverde | 239 | 216 | 23 |
| 2004-06-08 | @ TOR | 55 | L 1-7 | 30-25 | 1 | 16,499 | Hideo Nomo | Ted Lilly | Ted Lilly | Hideo Nomo | | 240 | 223 | 17 |
| 2004-06-09 | @ TOR | 56 | L 0-4 | 30-26 | 2 | 18,003 | Jose Lima | Miguel Batista | Miguel Batista | Jose Lima | | 240 | 227 | 13 |
| 2004-06-10 | @ TOR | 57 | W 6-1 | 31-26 | 1 | 16,267 | Kazuhisa Ishii | Josh Towers | Kazuhisa Ishii | Josh Towers | | 246 | 228 | 18 |
| 2004-06-11 | @ BOS | 58 | L 1-2 | 31-27 | 2 | 35,173 | Odalis Perez | Derek Lowe | Keith Foulke | Tom Martin | | 247 | 230 | 17 |
| 2004-06-12 | @ BOS | 59 | W 14-5 | 32-27 | 1 | 34,671 | Jeff Weaver | Tim Wakefield | Jeff Weaver | Tim Wakefield | | 261 | 235 | 26 |
| 2004-06-13 | @ BOS | 60 | L 1-4 | 32-28 | 1 | 35,068 | Hideo Nomo | Pedro Martinez | Pedro Martinez | Hideo Nomo | Keith Foulke | 262 | 239 | 23 |
| 2004-06-15 | vs BAL | 61 | W 5-1 | 33-28 | 1 | 29,711 | Jose Lima | Daniel Cabrera | Jose Lima | Daniel Cabrera | Eric Gagne | 267 | 240 | 27 |
| 2004-06-16 | vs BAL | 62 | W 6-3 | 34-28 | 1 | 35,070 | Odalis Perez | Matt Riley | Odalis Perez | Matt Riley | Eric Gagne | 273 | 243 | 30 |
| 2004-06-17 | vs BAL | 63 | W 4-3 | 35-28 | 1 | 30,465 | Kazuhisa Ishii | Erik Bedard | Guillermo Mota | Rodrigo Lopez | Eric Gagne | 277 | 246 | 31 |
| 2004-06-18 | vs NYA | 64 | W 6-3 | 36-28 | 1 | 55,207 | Jeff Weaver | Javier Vazquez | Jeff Weaver | Javier Vazquez | Eric Gagne | 283 | 249 | 34 |
| 2004-06-19 | vs NYA | 65 | L 2-6 | 36-29 | 1 | 54,876 | Hideo Nomo | Brad Halsey | Brad Halsey | Hideo Nomo | | 285 | 255 | 30 |
| 2004-06-20 | vs NYA | 66 | W 5-4 | 37-29 | 1 | 55,157 | Jose Lima | Jose Contreras | Jose Lima | Jose Contreras | Eric Gagne | 290 | 259 | 31 |
| 2004-06-21 | @ SFN | 67 | L 2-3 | 37-30 | 1 | 41,453 | Odalis Perez | Kirk Rueter | Matt Herges | Guillermo Mota | | 292 | 262 | 30 |
| 2004-06-22 | @ SFN | 68 | L 5-11 | 37-31 | 2 | 41,703 | Kazuhisa Ishii | Dustin Hermanson | Jim Brower | Wilson Alvarez | | 297 | 273 | 24 |
| 2004-06-23 | @ SFN | 69 | L 2-3 | 37-32 | 2 | 42,340 | Jeff Weaver | Jerome Williams | Jerome Williams | Jeff Weaver | Matt Herges | 299 | 276 | 23 |
| 2004-06-24 | @ SFN | 70 | L 3-9 | 37-33 | 2 | 42,621 | Hideo Nomo | Brett Tomko | Brett Tomko | Hideo Nomo | | 302 | 285 | 17 |
| 2004-06-25 | vs ANA | 71 | L 0-13 | 37-34 | 3 | 54,617 | Jose Lima | Jarrod Washburn | Jarrod Washburn | Jose Lima | | 302 | 298 | 4 |
| 2004-06-26 | vs ANA | 72 | L 5-7 | 37-35 | 3 | 52,715 | Odalis Perez | Aaron Sele | Brendan Donnelly | Guillermo Mota | Francisco Rodriguez | 307 | 305 | 2 |
| 2004-06-27 | vs ANA | 73 | W 10-5 | 38-35 | 3 | 54,333 | Kazuhisa Ishii | Bartolo Colon | Kazuhisa Ishii | Bartolo Colon | | 317 | 310 | 7 |
| 2004-06-29 | vs SFN | 74 | W 2-1 | 39-35 | 3 | 51,113 | Jeff Weaver | Noah Lowry | Guillermo Mota | Jim Brower | Eric Gagne | 319 | 311 | 8 |
| 2004-06-30 | vs SFN | 75 | L 1-7 | 39-36 | 3 | 47,081 | Hideo Nomo | Brett Tomko | Brett Tomko | Hideo Nomo | | 320 | 318 | 2 |
| 2004-07-01 | vs SFN | 76 | W 5-4 | 40-36 | 2 | 54,717 | Jose Lima | Jason Schmidt | Guillermo Mota | Felix Rodriguez | Eric Gagne | 325 | 322 | 3 |
| 2004-07-02 | @ ANA | 77 | L 3-7 | 40-37 | 3 | 43,816 | Kazuhisa Ishii | Aaron Sele | Aaron Sele | Kazuhisa Ishii | | 328 | 329 | -1 |
| 2004-07-03 | @ ANA | 78 | W 8-5 | 41-37 | 3 | 43,686 | Edwin Jackson | Bartolo Colon | Guillermo Mota | Bartolo Colon | Eric Gagne | 336 | 334 | 2 |
| 2004-07-04 | @ ANA | 79 | W 6-2 | 42-37 | 3 | 43,823 | Jeff Weaver | Kelvim Escobar | Jeff Weaver | Kelvim Escobar | | 342 | 336 | 6 |
| 2004-07-05 | vs ARI | 80 | W 6-5 | 43-37 | 3 | 32,929 | Wilson Alvarez | Brandon Webb | Giovanni Carrara | Brandon Villafuerte | | 348 | 341 | 7 |
| 2004-07-06 | vs ARI | 81 | W 4-1 | 44-37 | 2 | 25,139 | Jose Lima | Casey Fossum | Jose Lima | Casey Fossum | Eric Gagne | 352 | 342 | 10 |
| 2004-07-07 | vs ARI | 82 | W 11-0 | 45-37 | 1 | 27,899 | Kazuhisa Ishii | Steve Sparks | Kazuhisa Ishii | Steve Sparks | | 363 | 342 | 21 |
| 2004-07-08 | vs HOU | 83 | W 7-2 | 46-37 | 1 | 33,324 | Edwin Jackson | Brandon Duckworth | Edwin Jackson | Brandon Duckworth | Tom Martin | 370 | 344 | 26 |
| 2004-07-09 | vs HOU | 84 | L 2-3 | 46-38 | 1 | 52,783 | Jeff Weaver | Andy Pettitte | Andy Pettitte | Jeff Weaver | Brad Lidge | 372 | 347 | 25 |
| 2004-07-10 | vs HOU | 85 | W 3-1 | 47-38 | 1 | 46,321 | Wilson Alvarez | Roger Clemens | Wilson Alvarez | Roger Clemens | Eric Gagne | 375 | 348 | 27 |
| 2004-07-11 | vs HOU | 86 | W 7-4 | 48-38 | 1 | 40,484 | Jose Lima | Roy Oswalt | Jose Lima | Roy Oswalt | | 382 | 352 | 30 |
| 2004-07-15 | @ ARI | 87 | W 4-3 | 49-38 | 1 | 28,150 | Jeff Weaver | Randy Johnson | Wilson Alvarez | Randy Choate | Eric Gagne | 386 | 355 | 31 |
| 2004-07-16 | @ ARI | 88 | W 6-2 | 50-38 | 1 | 29,255 | Kazuhisa Ishii | Brandon Webb | Kazuhisa Ishii | Brandon Webb | | 392 | 357 | 35 |
| 2004-07-17 | @ ARI | 89 | W 7-6 | 51-38 | 1 | 37,027 | Odalis Perez | Casey Fossum | Guillermo Mota | Brian Bruney | Eric Gagne | 399 | 363 | 36 |
| 2004-07-18 | @ ARI | 90 | W 10-3 | 52-38 | 1 | 29,131 | Jose Lima | Elmer Dessens | Jose Lima | Elmer Dessens | | 409 | 366 | 43 |
| 2004-07-19 | @ HOU | 91 | W 7-6 | 53-38 | 1 | 35,155 | Wilson Alvarez | Brandon Duckworth | Giovanni Carrara | Dan Miceli | Eric Gagne | 416 | 372 | 44 |
| 2004-07-20 | @ HOU | 92 | W 7-5 | 54-38 | 1 | 34,154 | Jeff Weaver | Peter Munro | Jeff Weaver | David Weathers | Eric Gagne | 423 | 377 | 46 |
| 2004-07-21 | vs COL | 93 | L 5-6 | 54-39 | 1 | 34,343 | Kazuhisa Ishii | Shawn Estes | Shawn Estes | Kazuhisa Ishii | Shawn Chacon | 428 | 383 | 45 |
| 2004-07-22 | vs COL | 94 | W 4-2 | 55-39 | 1 | 34,276 | Odalis Perez | Aaron Cook | Guillermo Mota | Tim Harikkala | Eric Gagne | 432 | 385 | 47 |
| 2004-07-23 | vs SDN | 95 | W 3-2 | 56-39 | 1 | 55,311 | Jose Lima | Brian Lawrence | Eric Gagne | Rod Beck | | 435 | 387 | 48 |
| 2004-07-24 | vs SDN | 96 | W 12-2 | 57-39 | 1 | 52,217 | Wilson Alvarez | Ismael Valdez | Wilson Alvarez | Ismael Valdez | | 447 | 389 | 58 |
| 2004-07-25 | vs SDN | 97 | L 0-3 | 57-40 | 1 | 46,884 | Jeff Weaver | Adam Eaton | Adam Eaton | Jeff Weaver | Trevor Hoffman | 447 | 392 | 55 |
| 2004-07-26 | @ COL | 98 | W 9-7 | 58-40 | 1 | 24,725 | Kazuhisa Ishii | Shawn Estes | Duaner Sanchez | Allan Simpson | Eric Gagne | 456 | 399 | 57 |
| 2004-07-27 | @ COL | 99 | L 2-7 | 58-41 | 1 | 27,934 | Odalis Perez | Aaron Cook | Aaron Cook | Odalis Perez | | 458 | 406 | 52 |
| 2004-07-28 | @ COL | 100 | L 4-5 | 58-42 | 1 | 25,492 | Jose Lima | Jeff Fassero | Steve Reed | Guillermo Mota | Shawn Chacon | 462 | 411 | 51 |
| 2004-07-29 | @ COL | 101 | W 3-2 | 59-42 | 1 | 28,472 | Wilson Alvarez | Jamey Wright | Wilson Alvarez | Scott Dohmann | Eric Gagne | 465 | 413 | 52 |
| 2004-07-30 | @ SDN | 102 | W 12-3 | 60-42 | 1 | 42,552 | Jeff Weaver | Adam Eaton | Jeff Weaver | Adam Eaton | | 477 | 416 | 61 |
| 2004-07-31 | @ SDN | 103 | L 2-3 | 60-43 | 1 | 43,726 | Kazuhisa Ishii | Jake Peavy | Akinori Otsuka | Darren Dreifort | Trevor Hoffman | 479 | 419 | 60 |
| 2004-08-01 | @ SDN | 104 | W 2-1 | 61-43 | 1 | 44,056 | Odalis Perez | David Wells | Eric Gagne | Ricky Stone | Darren Dreifort | 481 | 420 | 61 |
| 2004-08-03 | vs PIT | 105 | W 3-2 | 62-43 | 1 | 34,581 | Brad Penny | Oliver Perez | Brad Penny | Oliver Perez | Eric Gagne | 484 | 422 | 62 |
| 2004-08-04 | vs PIT | 106 | W 2-1 | 63-43 | 1 | 34,792 | Jose Lima | Josh Fogg | Jose Lima | Josh Fogg | Eric Gagne | 486 | 423 | 63 |
| 2004-08-05 | vs PIT | 107 | W 8-3 | 64-43 | 1 | 38,852 | Jeff Weaver | Sean Burnett | Jeff Weaver | Sean Burnett | | 494 | 426 | 68 |
| 2004-08-06 | vs PHI | 108 | L 5-9 | 64-44 | 1 | 53,977 | Kazuhisa Ishii | Randy Wolf | Roberto Hernandez | Eric Gagne | | 499 | 435 | 64 |
| 2004-08-07 | vs PHI | 109 | W 6-3 | 65-44 | 1 | 54,404 | Odalis Perez | Paul Abbott | Odalis Perez | Paul Abbott | Eric Gagne | 505 | 438 | 67 |
| 2004-08-08 | vs PHI | 110 | L 1-4 | 65-45 | 1 | 53,840 | Brad Penny | Brett Myers | Brett Myers | Brad Penny | | 506 | 442 | 64 |
| 2004-08-10 | @ CIN | 111 | W 5-2 | 66-45 | 1 | 26,295 | Jose Lima | Aaron Harang | Jose Lima | Aaron Harang | Eric Gagne | 511 | 444 | 67 |
| 2004-08-11 | @ CIN | 112 | W 11-1 | 67-45 | 1 | 39,933 | Jeff Weaver | Brandon Claussen | Jeff Weaver | Brandon Claussen | | 522 | 445 | 77 |
| 2004-08-12 | @ CIN | 113 | L 5-6 | 67-46 | 1 | 27,416 | Wilson Alvarez | Josh Hancock | Gabe White | Darren Dreifort | Danny Graves | 527 | 451 | 76 |
| 2004-08-13 | @ CHN | 114 | W 8-1 | 68-46 | 1 | 39,105 | Odalis Perez | Greg Maddux | Odalis Perez | Greg Maddux | | 535 | 452 | 83 |
| 2004-08-14 | @ CHN | 115 | L 0-2 | 68-47 | 1 | 39,069 | Kazuhisa Ishii | Kerry Wood | Kerry Wood | Kazuhisa Ishii | Mike Remlinger | 535 | 454 | 81 |
| 2004-08-15 | @ CHN | 116 | W 8-5 | 69-47 | 1 | 39,079 | Jose Lima | Mark Prior | Duaner Sanchez | Kyle Farnsworth | Eric Gagne | 543 | 459 | 84 |
| 2004-08-16 | vs FLO | 117 | L 2-4 | 69-48 | 1 | 53,121 | Jeff Weaver | Carl Pavano | Carl Pavano | Darren Dreifort | Armando Benitez | 545 | 463 | 82 |
| 2004-08-17 | vs FLO | 118 | W 6-1 | 70-48 | 1 | 45,731 | Wilson Alvarez | A.J. Burnett | Wilson Alvarez | A.J. Burnett | | 551 | 464 | 87 |
| 2004-08-18 | vs FLO | 119 | L 4-6 | 70-49 | 1 | 46,241 | Odalis Perez | Ismael Valdez | Guillermo Mota | Eric Gagne | Armando Benitez | 555 | 470 | 85 |
| 2004-08-19 | vs ATL | 120 | L 5-6 | 70-50 | 1 | 42,287 | Kazuhisa Ishii | Russ Ortiz | Chris Reitsma | Eric Gagne | John Smoltz | 560 | 476 | 84 |
| 2004-08-20 | vs ATL | 121 | W 3-2 | 71-50 | 1 | 54,993 | Jose Lima | John Thomson | Giovanni Carrara | Juan Cruz | | 563 | 478 | 85 |
| 2004-08-21 | vs ATL | 122 | W 7-4 | 72-50 | 1 | 52,398 | Jeff Weaver | Mike Hampton | Jeff Weaver | Mike Hampton | Giovanni Carrara | 570 | 482 | 88 |
| 2004-08-22 | vs ATL | 123 | L 1-10 | 72-51 | 1 | 49,513 | Wilson Alvarez | Jaret Wright | Jaret Wright | Wilson Alvarez | | 571 | 492 | 79 |
| 2004-08-23 | @ MON | 124 | L 7-8 | 72-52 | 1 | 8,639 | Odalis Perez | Sun-Woo Kim | Chad Cordero | Giovanni Carrara | | 578 | 500 | 78 |
| 2004-08-24 | @ MON | 125 | W 10-2 | 73-52 | 1 | 8,109 | Kazuhisa Ishii | Rocky Biddle | Kazuhisa Ishii | Rocky Biddle | | 588 | 502 | 86 |
| 2004-08-25 | @ MON | 126 | L 3-6 | 73-53 | 1 | 7,570 | Jose Lima | Tony Armas | Joe Horgan | Jose Lima | Luis Ayala | 591 | 508 | 83 |
| 2004-08-26 | @ MON | 127 | W 10-3 | 74-53 | 1 | 18,520 | Jeff Weaver | Livan Hernandez | Jeff Weaver | Livan Hernandez | | 601 | 511 | 90 |
| 2004-08-27 | @ NYN | 128 | L 2-9 | 74-54 | 1 | 42,694 | Wilson Alvarez | Tom Glavine | Tom Glavine | Wilson Alvarez | | 603 | 520 | 83 |
| 2004-08-28 | @ NYN | 129 | W 4-2 | 75-54 | 1 | 40,660 | Odalis Perez | Jae Weong Seo | Giovanni Carrara | Mike Stanton | Eric Gagne | 607 | 522 | 85 |
| 2004-08-29 | @ NYN | 130 | W 10-2 | 76-54 | 1 | 33,582 | Kazuhisa Ishii | Kris Benson | Kazuhisa Ishii | Kris Benson | | 617 | 524 | 93 |
| 2004-08-31 | @ ARI | 131 | W 4-1 | 77-54 | 1 | 39,167 | Jeff Weaver | Randy Johnson | Eric Gagne | Brian Bruney | Giovanni Carrara | 621 | 525 | 96 |
| 2004-09-01 | @ ARI | 132 | L 1-3 | 77-55 | 1 | 34,149 | Hideo Nomo | Brandon Webb | Brandon Webb | Hideo Nomo | Greg Aquino | 622 | 528 | 94 |
| 2004-09-02 | @ ARI | 133 | W 8-4 | 78-55 | 1 | 33,224 | Odalis Perez | Casey Fossum | Yhency Brazoban | Shane Nance | Eric Gagne | 630 | 532 | 98 |
| 2004-09-03 | @ SLN | 134 | L 0-3 | 78-56 | 1 | 37,524 | Jose Lima | Matt Morris | Matt Morris | Jose Lima | | 630 | 535 | 95 |
| 2004-09-04 | @ SLN | 135 | L 1-5 | 78-57 | 1 | 45,692 | Kazuhisa Ishii | Jason Marquis | Jason Marquis | Kazuhisa Ishii | | 631 | 540 | 91 |
| 2004-09-05 | @ SLN | 136 | L 5-6 | 78-58 | 1 | 43,611 | Jeff Weaver | Woody Williams | Ray King | Giovanni Carrara | | 636 | 546 | 90 |
| 2004-09-07 | vs ARI | 137 | W 8-2 | 79-58 | 1 | 35,078 | Hideo Nomo | Brandon Webb | Hideo Nomo | Brandon Webb | | 644 | 548 | 96 |
| 2004-09-08 | vs ARI | 138 | W 6-5 | 80-58 | 1 | 28,888 | Odalis Perez | Casey Fossum | Eric Gagne | Mike Koplove | | 650 | 553 | 97 |
| 2004-09-09 | vs ARI | 139 | W 5-3 | 81-58 | 1 | 27,287 | Jose Lima | Edgar Gonzalez | Jose Lima | Edgar Gonzalez | Eric Gagne | 655 | 556 | 99 |
| 2004-09-10 | vs SLN | 140 | W 7-6 | 82-58 | 1 | 54,119 | Kazuhisa Ishii | Jason Marquis | Giovanni Carrara | Kiko Calero | Eric Gagne | 662 | 562 | 100 |
| 2004-09-11 | vs SLN | 141 | W 6-5 | 83-58 | 1 | 53,494 | Jeff Weaver | Woody Williams | Scott Stewart | Cal Eldred | Eric Gagne | 668 | 567 | 101 |
| 2004-09-12 | vs SLN | 142 | L 6-7 | 83-59 | 1 | 54,000 | Hideo Nomo | Chris Carpenter | Chris Carpenter | Edwin Jackson | Jason Isringhausen | 674 | 574 | 100 |
| 2004-09-13 | vs SDN | 143 | L 7-9 | 83-60 | 1 | 36,050 | Odalis Perez | David Wells | David Wells | Odalis Perez | Trevor Hoffman | 681 | 583 | 98 |
| 2004-09-14 | vs SDN | 144 | W 6-3 | 84-60 | 1 | 29,704 | Jose Lima | Justin Germano | Jose Lima | Justin Germano | Eric Gagne | 687 | 586 | 101 |
| 2004-09-15 | vs SDN | 145 | L 3-7 | 84-61 | 1 | 34,105 | Wilson Alvarez | Brian Lawrence | Brian Lawrence | Wilson Alvarez | Trevor Hoffman | 690 | 593 | 97 |
| 2004-09-16 | vs SDN | 146 | L 0-3 | 84-62 | 1 | 43,185 | Jeff Weaver | Adam Eaton | Adam Eaton | Jeff Weaver | Trevor Hoffman | 690 | 596 | 94 |
| 2004-09-17 | @ COL | 147 | W 8-6 | 85-62 | 1 | 23,572 | Hideo Nomo | Jamey Wright | Eric Gagne | Shawn Chacon | | 698 | 602 | 96 |
| 2004-09-18 | @ COL | 148 | L 1-8 | 85-63 | 1 | 21,664 | Odalis Perez | Joe Kennedy | Joe Kennedy | Odalis Perez | | 699 | 610 | 89 |
| 2004-09-19 | @ COL | 149 | W 7-6 | 86-63 | 1 | 27,175 | Edwin Jackson | Jason Jennings | Yhency Brazoban | Shawn Chacon | Eric Gagne | 706 | 616 | 90 |
| 2004-09-21 | @ SDN | 150 | L 4-9 | 86-64 | 1 | 39,428 | Jeff Weaver | Adam Eaton | Adam Eaton | Jeff Weaver | | 710 | 625 | 85 |
| 2004-09-22 | @ SDN | 151 | L 0-4 | 86-65 | 1 | 41,303 | Brad Penny | Jake Peavy | Jake Peavy | Brad Penny | | 710 | 629 | 81 |
| 2004-09-23 | @ SDN | 152 | W 9-6 | 87-65 | 1 | 42,159 | Kazuhisa Ishii | Brian Lawrence | Yhency Brazoban | Brian Lawrence | Eric Gagne | 719 | 635 | 84 |
| 2004-09-24 | @ SFN | 153 | W 3-2 | 88-65 | 1 | 42,528 | Odalis Perez | Kirk Rueter | Odalis Perez | Kirk Rueter | Eric Gagne | 722 | 637 | 85 |
| 2004-09-25 | @ SFN | 154 | L 5-9 | 88-66 | 1 | 42,486 | Jose Lima | Brad Hennessey | Scott Eyre | Yhency Brazoban | | 727 | 646 | 81 |
| 2004-09-26 | @ SFN | 155 | W 7-4 | 89-66 | 1 | 42,549 | Jeff Weaver | Brett Tomko | Jeff Weaver | Brett Tomko | Eric Gagne | 734 | 650 | 84 |
| 2004-09-27 | vs COL | 156 | W 8-7 | 90-66 | 1 | 36,958 | Edwin Jackson | Shawn Estes | Yhency Brazoban | Steve Reed | | 742 | 657 | 85 |
| 2004-09-28 | vs COL | 157 | W 5-4 | 91-66 | 1 | 33,588 | Kazuhisa Ishii | Jamey Wright | Elmer Dessens | Tim Harikkala | | 747 | 661 | 86 |
| 2004-09-29 | vs COL | 158 | L 1-4 | 91-67 | 1 | 43,304 | Odalis Perez | Jeff Francis | Brian Fuentes | Yhency Brazoban | Chin-hui Tsao | 748 | 665 | 83 |
| 2004-09-30 | vs COL | 159 | W 4-2 | 92-67 | 1 | 53,438 | Jose Lima | Jason Jennings | Yhency Brazoban | Brian Fuentes | | 752 | 667 | 85 |
| 2004-10-01 | vs SFN | 160 | L 2-4 | 92-68 | 1 | 54,888 | Jeff Weaver | Kirk Rueter | Kirk Rueter | Jeff Weaver | Dustin Hermanson | 754 | 671 | 83 |
| 2004-10-02 | vs SFN | 161 | W 7-3 | 93-68 | 1 | 54,594 | Elmer Dessens | Brett Tomko | Yhency Brazoban | Dustin Hermanson | | 761 | 674 | 87 |
| 2004-10-03 | vs SFN | 162 | L 0-10 | 93-69 | 1 | 54,968 | Kazuhisa Ishii | Jason Schmidt | Jason Schmidt | Kazuhisa Ishii | | 761 | 684 | 77 |