| 2004-04-05 | @ LAN | 1 | W 8-2 | 1-0 | 1 | 53,850 | Brian Lawrence | Hideo Nomo | Brian Lawrence | Hideo Nomo | | 8 | 2 | 6 |
| 2004-04-06 | @ LAN | 2 | L 4-5 | 1-1 | 4 | 26,437 | Jake Peavy | Odalis Perez | Eric Gagne | Akinori Otsuka | | 12 | 7 | 5 |
| 2004-04-07 | @ LAN | 3 | L 1-2 | 1-2 | 5 | 26,932 | Adam Eaton | Jeff Weaver | Jose Lima | Eddie Oropesa | | 13 | 9 | 4 |
| 2004-04-08 | vs SFN | 4 | W 4-3 | 2-2 | 3 | 41,400 | David Wells | Dustin Hermanson | Eddie Oropesa | Matt Herges | | 17 | 12 | 5 |
| 2004-04-10 | vs SFN | 5 | W 6-4 | 3-2 | 2 | 41,625 | Brian Lawrence | Kirk Rueter | Scott Linebrink | Jim Brower | Trevor Hoffman | 23 | 16 | 7 |
| 2004-04-11 | vs SFN | 6 | L 3-6 | 3-3 | 2 | 41,492 | Jake Peavy | Brett Tomko | Jason Christiansen | Jay Witasick | Matt Herges | 26 | 22 | 4 |
| 2004-04-13 | vs LAN | 7 | W 8-3 | 4-3 | 3 | 35,156 | Adam Eaton | Jeff Weaver | Adam Eaton | Jeff Weaver | | 34 | 25 | 9 |
| 2004-04-14 | vs LAN | 8 | L 4-11 | 4-4 | 4 | 34,558 | David Wells | Kazuhisa Ishii | Kazuhisa Ishii | David Wells | | 38 | 36 | 2 |
| 2004-04-15 | vs LAN | 9 | L 5-7 | 4-5 | 4 | 40,104 | Brian Lawrence | Hideo Nomo | Hideo Nomo | Brian Lawrence | Eric Gagne | 43 | 43 | 0 |
| 2004-04-16 | vs ARI | 10 | L 0-5 | 4-6 | 5 | 37,300 | Jake Peavy | Randy Johnson | Randy Johnson | Jake Peavy | | 43 | 48 | -5 |
| 2004-04-17 | vs ARI | 11 | W 3-2 | 5-6 | 2 | 42,261 | Ismael Valdez | Brandon Webb | Ismael Valdez | Brandon Webb | Trevor Hoffman | 46 | 50 | -4 |
| 2004-04-18 | vs ARI | 12 | W 6-5 | 6-6 | 2 | 41,730 | Adam Eaton | Steve Sparks | Eddie Oropesa | Matt Mantei | | 52 | 55 | -3 |
| 2004-04-19 | @ SFN | 13 | L 3-4 | 6-7 | 2 | 33,361 | David Wells | Jerome Williams | Jerome Williams | David Wells | Jim Brower | 55 | 59 | -4 |
| 2004-04-20 | @ SFN | 14 | W 9-5 | 7-7 | 2 | 33,825 | Brian Lawrence | Dustin Hermanson | Brian Lawrence | Dustin Hermanson | | 64 | 64 | 0 |
| 2004-04-21 | @ SFN | 15 | W 11-0 | 8-7 | 2 | 34,545 | Jake Peavy | Jason Schmidt | Jake Peavy | Jason Schmidt | | 75 | 64 | 11 |
| 2004-04-22 | @ SFN | 16 | W 9-4 | 9-7 | 2 | 36,283 | Ismael Valdez | Kirk Rueter | Ismael Valdez | Kirk Rueter | | 84 | 68 | 16 |
| 2004-04-23 | @ ARI | 17 | L 2-5 | 9-8 | 2 | 30,028 | Adam Eaton | Casey Daigle | Mike Koplove | Adam Eaton | Matt Mantei | 86 | 73 | 13 |
| 2004-04-24 | @ ARI | 18 | W 4-2 | 10-8 | 2 | 32,657 | David Wells | Steve Sparks | Akinori Otsuka | Oscar Villarreal | Trevor Hoffman | 90 | 75 | 15 |
| 2004-04-25 | @ ARI | 19 | L 7-12 | 10-9 | 2 | 32,553 | Brian Lawrence | Elmer Dessens | Elmer Dessens | Brian Lawrence | | 97 | 87 | 10 |
| 2004-04-26 | vs MON | 20 | W 3-2 | 11-9 | 2 | 25,438 | Jake Peavy | Livan Hernandez | Akinori Otsuka | Luis Ayala | | 100 | 89 | 11 |
| 2004-04-27 | vs MON | 21 | W 3-0 | 12-9 | 2 | 25,473 | Ismael Valdez | John Patterson | Ismael Valdez | John Patterson | Trevor Hoffman | 103 | 89 | 14 |
| 2004-04-28 | vs MON | 22 | W 5-4 | 13-9 | 2 | 24,079 | Adam Eaton | Claudio Vargas | Antonio Osuna | Luis Ayala | Trevor Hoffman | 108 | 93 | 15 |
| 2004-04-29 | vs MON | 23 | W 2-1 | 14-9 | 2 | 24,581 | David Wells | Tomo Ohka | David Wells | Tomo Ohka | Trevor Hoffman | 110 | 94 | 16 |
| 2004-04-30 | vs NYN | 24 | W 7-6 | 15-9 | 2 | 41,971 | Brian Lawrence | Tyler Yates | Brian Lawrence | Tyler Yates | Akinori Otsuka | 117 | 100 | 17 |
| 2004-05-01 | vs NYN | 25 | W 3-1 | 16-9 | 2 | 42,064 | Jake Peavy | Al Leiter | Jake Peavy | John Franco | Trevor Hoffman | 120 | 101 | 19 |
| 2004-05-02 | vs NYN | 26 | L 2-6 | 16-10 | 2 | 41,965 | Ismael Valdez | Tom Glavine | Tom Glavine | Ismael Valdez | | 122 | 107 | 15 |
| 2004-05-04 | @ ATL | 27 | L 2-4 | 16-11 | 2 | 22,046 | Adam Eaton | Russ Ortiz | Russ Ortiz | Adam Eaton | John Smoltz | 124 | 111 | 13 |
| 2004-05-05 | @ ATL | 28 | W 2-0 | 17-11 | 2 | 21,444 | David Wells | Jaret Wright | David Wells | Jaret Wright | Trevor Hoffman | 126 | 111 | 15 |
| 2004-05-06 | @ ATL | 29 | W 7-3 | 18-11 | 2 | 26,137 | Brian Lawrence | Mike Hampton | Brian Lawrence | Mike Hampton | | 133 | 114 | 19 |
| 2004-05-07 | @ FLO | 30 | L 1-3 | 18-12 | 2 | 17,703 | Jake Peavy | Carl Pavano | Carl Pavano | Jake Peavy | Armando Benitez | 134 | 117 | 17 |
| 2004-05-08 | @ FLO | 31 | W 6-3 | 19-12 | 2 | 30,655 | Ismael Valdez | Darren Oliver | Akinori Otsuka | Frank Gracesqui | Trevor Hoffman | 140 | 120 | 20 |
| 2004-05-09 | @ FLO | 32 | L 4-7 | 19-13 | 2 | 16,497 | Adam Eaton | Josh Beckett | Josh Beckett | Adam Eaton | Armando Benitez | 144 | 127 | 17 |
| 2004-05-11 | vs CIN | 33 | L 3-6 | 19-14 | 2 | 28,809 | David Wells | Aaron Harang | Aaron Harang | David Wells | Danny Graves | 147 | 133 | 14 |
| 2004-05-12 | vs CIN | 34 | W 2-1 | 20-14 | 2 | 27,559 | Brian Lawrence | Cory Lidle | Brian Lawrence | Cory Lidle | Trevor Hoffman | 149 | 134 | 15 |
| 2004-05-13 | vs CIN | 35 | W 8-2 | 21-14 | 2 | 32,491 | Jake Peavy | Jose Acevedo | Jake Peavy | Jose Acevedo | | 157 | 136 | 21 |
| 2004-05-14 | vs CHN | 36 | L 1-6 | 21-15 | 2 | 41,938 | Ismael Valdez | Greg Maddux | Greg Maddux | Ismael Valdez | | 158 | 142 | 16 |
| 2004-05-15 | vs CHN | 37 | L 5-7 | 21-16 | 2 | 42,064 | Adam Eaton | Sergio Mitre | Sergio Mitre | Adam Eaton | LaTroy Hawkins | 163 | 149 | 14 |
| 2004-05-16 | vs CHN | 38 | L 2-4 | 21-17 | 2 | 42,000 | David Wells | Glendon Rusch | Francis Beltran | David Wells | Joe Borowski | 165 | 153 | 12 |
| 2004-05-19 | @ PIT | 39 | W 6-3 | 23-17 | 2 | 0 | Brian Lawrence | Kris Benson | Brian Lawrence | Mike Johnston | Trevor Hoffman | 171 | 156 | 15 |
| 2004-05-19 | @ PIT | 40 | W 7-3 | 23-17 | 2 | 13,366 | Jake Peavy | Oliver Perez | Jake Peavy | Oliver Perez | | 178 | 159 | 19 |
| 2004-05-20 | @ PIT | 41 | L 7-9 | 23-18 | 2 | 11,029 | Ismael Valdez | Ryan Vogelsong | Mike Gonzalez | Brandon Puffer | Jose Mesa | 185 | 168 | 17 |
| 2004-05-21 | @ PHI | 42 | L 4-5 | 23-19 | 2 | 40,555 | Adam Eaton | Kevin Millwood | Ryan Madson | Akinori Otsuka | Tim Worrell | 189 | 173 | 16 |
| 2004-05-22 | @ PHI | 43 | W 9-6 | 24-19 | 2 | 43,634 | Justin Germano | Josh Hancock | Justin Germano | Roberto Hernandez | | 198 | 179 | 19 |
| 2004-05-23 | @ PHI | 44 | L 4-6 | 24-20 | 2 | 44,216 | Brian Lawrence | Vicente Padilla | Vicente Padilla | Brian Lawrence | Tim Worrell | 202 | 185 | 17 |
| 2004-05-25 | @ COL | 45 | W 11-6 | 25-20 | 2 | 33,799 | Ismael Valdez | Joe Kennedy | Scott Linebrink | Jeff Fassero | | 213 | 191 | 22 |
| 2004-05-26 | @ COL | 46 | L 6-13 | 25-21 | 2 | 28,129 | Adam Eaton | Jason Jennings | Jason Jennings | Adam Eaton | | 219 | 204 | 15 |
| 2004-05-27 | @ COL | 47 | W 4-3 | 26-21 | 1 | 24,543 | Justin Germano | Aaron Cook | Akinori Otsuka | Vladimir Nunez | Trevor Hoffman | 223 | 207 | 16 |
| 2004-05-28 | @ MIL | 48 | W 5-3 | 27-21 | 1 | 17,851 | Brian Lawrence | Doug Davis | Brian Lawrence | Doug Davis | Trevor Hoffman | 228 | 210 | 18 |
| 2004-05-29 | @ MIL | 49 | L 3-4 | 27-22 | 1 | 29,499 | Dennis Tankersley | Wes Obermueller | Wes Obermueller | Dennis Tankersley | Danny Kolb | 231 | 214 | 17 |
| 2004-05-30 | @ MIL | 50 | W 5-2 | 28-22 | 1 | 27,168 | Ismael Valdez | Victor Santos | Ismael Valdez | Victor Santos | Trevor Hoffman | 236 | 216 | 20 |
| 2004-05-31 | vs COL | 51 | L 1-7 | 28-23 | 2 | 38,355 | Adam Eaton | Jason Jennings | Jason Jennings | Adam Eaton | | 237 | 223 | 14 |
| 2004-06-01 | vs COL | 52 | L 1-7 | 28-24 | 2 | 28,313 | Justin Germano | Aaron Cook | Aaron Cook | Justin Germano | | 238 | 230 | 8 |
| 2004-06-02 | vs COL | 53 | W 2-1 | 29-24 | 2 | 38,521 | Brian Lawrence | Shawn Estes | Trevor Hoffman | Brian Fuentes | | 240 | 231 | 9 |
| 2004-06-04 | vs MIL | 54 | L 1-3 | 29-25 | 2 | 41,828 | Dennis Tankersley | Victor Santos | Victor Santos | Dennis Tankersley | Danny Kolb | 241 | 234 | 7 |
| 2004-06-05 | vs MIL | 55 | W 4-0 | 30-25 | 2 | 39,817 | Ismael Valdez | Wes Obermueller | Ismael Valdez | Wes Obermueller | | 245 | 234 | 11 |
| 2004-06-06 | vs MIL | 56 | W 8-3 | 31-25 | 2 | 40,348 | Adam Eaton | Doug Davis | Adam Eaton | Doug Davis | | 253 | 237 | 16 |
| 2004-06-08 | @ BOS | 57 | L 0-1 | 31-26 | 2 | 35,205 | David Wells | Pedro Martinez | Pedro Martinez | Antonio Osuna | Keith Foulke | 253 | 238 | 15 |
| 2004-06-09 | @ BOS | 58 | W 8-1 | 32-26 | 1 | 35,064 | Brian Lawrence | Bronson Arroyo | Brian Lawrence | Bronson Arroyo | | 261 | 239 | 22 |
| 2004-06-10 | @ BOS | 59 | L 3-9 | 32-27 | 2 | 35,068 | Ismael Valdez | Curt Schilling | Curt Schilling | Ismael Valdez | | 264 | 248 | 16 |
| 2004-06-11 | @ NYA | 60 | W 10-2 | 33-27 | 1 | 49,855 | Adam Eaton | Mike Mussina | Adam Eaton | Felix Heredia | Akinori Otsuka | 274 | 250 | 24 |
| 2004-06-12 | @ NYA | 61 | L 2-3 | 33-28 | 2 | 54,280 | Dennis Tankersley | Jon Lieber | Jon Lieber | Dennis Tankersley | Mariano Rivera | 276 | 253 | 23 |
| 2004-06-13 | @ NYA | 62 | L 5-6 | 33-29 | 2 | 52,754 | David Wells | Javier Vazquez | Felix Heredia | Rod Beck | | 281 | 259 | 22 |
| 2004-06-15 | vs TBA | 63 | L 2-5 | 33-30 | 2 | 28,933 | Brian Lawrence | Mark Hendrickson | Mark Hendrickson | Brian Lawrence | | 283 | 264 | 19 |
| 2004-06-16 | vs TBA | 64 | L 6-9 | 33-31 | 3 | 26,645 | Ismael Valdez | Victor Zambrano | Victor Zambrano | Scott Linebrink | Danys Baez | 289 | 273 | 16 |
| 2004-06-17 | vs TBA | 65 | L 1-4 | 33-32 | 3 | 28,321 | Adam Eaton | Chad Gaudin | Chad Gaudin | Adam Eaton | Danys Baez | 290 | 277 | 13 |
| 2004-06-18 | vs TOR | 66 | L 2-3 | 33-33 | 3 | 40,511 | David Wells | Ted Lilly | Ted Lilly | David Wells | Jason Frasor | 292 | 280 | 12 |
| 2004-06-19 | vs TOR | 67 | W 3-2 | 34-33 | 3 | 40,307 | Dennis Tankersley | Josh Towers | Scott Linebrink | Justin Speier | Trevor Hoffman | 295 | 282 | 13 |
| 2004-06-20 | vs TOR | 68 | L 0-3 | 34-34 | 3 | 41,060 | Brian Lawrence | Miguel Batista | Miguel Batista | Brian Lawrence | Jason Frasor | 295 | 285 | 10 |
| 2004-06-21 | vs ARI | 69 | W 3-1 | 35-34 | 3 | 29,253 | Ismael Valdez | Casey Fossum | Ismael Valdez | Casey Fossum | Trevor Hoffman | 298 | 286 | 12 |
| 2004-06-22 | vs ARI | 70 | W 2-1 | 36-34 | 3 | 30,933 | Adam Eaton | Steve Sparks | Trevor Hoffman | Mike Koplove | | 300 | 287 | 13 |
| 2004-06-23 | vs ARI | 71 | W 4-3 | 37-34 | 3 | 37,304 | David Wells | Randy Johnson | Akinori Otsuka | Elmer Dessens | | 304 | 290 | 14 |
| 2004-06-25 | @ SEA | 72 | W 3-2 | 38-34 | 2 | 40,918 | Brian Lawrence | Freddy Garcia | Brian Lawrence | Freddy Garcia | Trevor Hoffman | 307 | 292 | 15 |
| 2004-06-26 | @ SEA | 73 | L 3-7 | 38-35 | 2 | 39,272 | Ismael Valdez | Ron Villone | Julio Mateo | Ismael Valdez | | 310 | 299 | 11 |
| 2004-06-27 | @ SEA | 74 | W 5-1 | 39-35 | 2 | 43,649 | Adam Eaton | Jamie Moyer | Adam Eaton | Jamie Moyer | | 315 | 300 | 15 |
| 2004-06-28 | @ ARI | 75 | W 10-5 | 40-35 | 2 | 29,411 | David Wells | Shane Reynolds | David Wells | Shane Reynolds | | 325 | 305 | 20 |
| 2004-06-29 | @ ARI | 76 | W 3-2 | 41-35 | 2 | 34,633 | Brian Sweeney | Randy Johnson | Brian Sweeney | Randy Johnson | Trevor Hoffman | 328 | 307 | 21 |
| 2004-06-30 | @ ARI | 77 | L 5-8 | 41-36 | 2 | 24,275 | Brian Lawrence | Brandon Webb | Steve Randolph | Blaine Neal | Mike Koplove | 333 | 315 | 18 |
| 2004-07-01 | @ ARI | 78 | L 5-7 | 41-37 | 3 | 22,631 | Ismael Valdez | Casey Fossum | Casey Fossum | Ismael Valdez | Mike Koplove | 338 | 322 | 16 |
| 2004-07-02 | vs KCA | 79 | W 7-5 | 42-37 | 2 | 38,965 | Jake Peavy | Dennys Reyes | Jake Peavy | Dennys Reyes | Trevor Hoffman | 345 | 327 | 18 |
| 2004-07-03 | vs KCA | 80 | W 5-4 | 43-37 | 2 | 43,152 | Adam Eaton | Darrell May | Scott Linebrink | Scott Sullivan | Trevor Hoffman | 350 | 331 | 19 |
| 2004-07-04 | vs KCA | 81 | W 7-1 | 44-37 | 2 | 31,490 | David Wells | Mike Wood | David Wells | Mike Wood | | 357 | 332 | 25 |
| 2004-07-05 | vs HOU | 82 | W 2-1 | 45-37 | 1 | 39,653 | Brian Lawrence | Roger Clemens | Brian Lawrence | Dan Miceli | Trevor Hoffman | 359 | 333 | 26 |
| 2004-07-06 | vs HOU | 83 | W 5-3 | 46-37 | 1 | 31,540 | Ismael Valdez | Peter Munro | Ismael Valdez | Peter Munro | Trevor Hoffman | 364 | 336 | 28 |
| 2004-07-07 | vs HOU | 84 | L 1-5 | 46-38 | 2 | 31,402 | Jake Peavy | Roy Oswalt | Roy Oswalt | Jake Peavy | Brad Lidge | 365 | 341 | 24 |
| 2004-07-08 | vs COL | 85 | L 1-5 | 46-39 | 2 | 32,403 | Adam Eaton | Jason Jennings | Jason Jennings | Adam Eaton | | 366 | 346 | 20 |
| 2004-07-09 | vs COL | 86 | L 5-6 | 46-40 | 3 | 41,168 | David Wells | Shawn Estes | Tim Harikkala | Trevor Hoffman | Shawn Chacon | 371 | 352 | 19 |
| 2004-07-10 | vs COL | 87 | L 2-6 | 46-41 | 3 | 37,644 | Brian Lawrence | Aaron Cook | Aaron Cook | Brian Lawrence | | 373 | 358 | 15 |
| 2004-07-11 | vs COL | 88 | W 4-2 | 47-41 | 3 | 41,188 | Ismael Valdez | Denny Stark | Ismael Valdez | Denny Stark | Trevor Hoffman | 377 | 360 | 17 |
| 2004-07-16 | @ HOU | 89 | W 5-1 | 48-41 | 3 | 39,106 | Jake Peavy | Andy Pettitte | Jake Peavy | Andy Pettitte | | 382 | 361 | 21 |
| 2004-07-17 | @ HOU | 90 | W 7-4 | 49-41 | 3 | 39,714 | David Wells | Roy Oswalt | David Wells | Roy Oswalt | Trevor Hoffman | 389 | 365 | 24 |
| 2004-07-18 | @ HOU | 91 | L 3-5 | 49-42 | 3 | 38,094 | Brian Lawrence | Roger Clemens | Roger Clemens | Brian Lawrence | Brad Lidge | 392 | 370 | 22 |
| 2004-07-19 | @ COL | 92 | W 13-6 | 50-42 | 3 | 25,530 | Ismael Valdez | Denny Stark | Ismael Valdez | Denny Stark | | 405 | 376 | 29 |
| 2004-07-20 | @ COL | 93 | W 9-7 | 51-42 | 3 | 26,770 | Adam Eaton | Jason Jennings | Adam Eaton | Jason Jennings | Trevor Hoffman | 414 | 383 | 31 |
| 2004-07-21 | @ SFN | 94 | W 7-1 | 52-42 | 2 | 42,505 | Jake Peavy | Kirk Rueter | Jake Peavy | Kirk Rueter | | 421 | 384 | 37 |
| 2004-07-22 | @ SFN | 95 | W 9-4 | 53-42 | 2 | 42,686 | David Wells | Jason Schmidt | David Wells | Jason Schmidt | | 430 | 388 | 42 |
| 2004-07-23 | @ LAN | 96 | L 2-3 | 53-43 | 2 | 55,311 | Brian Lawrence | Jose Lima | Eric Gagne | Rod Beck | | 432 | 391 | 41 |
| 2004-07-24 | @ LAN | 97 | L 2-12 | 53-44 | 3 | 52,217 | Ismael Valdez | Wilson Alvarez | Wilson Alvarez | Ismael Valdez | | 434 | 403 | 31 |
| 2004-07-25 | @ LAN | 98 | W 3-0 | 54-44 | 2 | 46,884 | Adam Eaton | Jeff Weaver | Adam Eaton | Jeff Weaver | Trevor Hoffman | 437 | 403 | 34 |
| 2004-07-26 | vs SFN | 99 | W 3-2 | 55-44 | 2 | 41,559 | Jake Peavy | Kirk Rueter | Scott Linebrink | Felix Rodriguez | Trevor Hoffman | 440 | 405 | 35 |
| 2004-07-27 | vs SFN | 100 | L 4-6 | 55-45 | 2 | 40,068 | David Wells | Jason Schmidt | Jason Schmidt | David Wells | Matt Herges | 444 | 411 | 33 |
| 2004-07-28 | vs SFN | 101 | W 9-4 | 56-45 | 2 | 37,548 | Brian Lawrence | Dustin Hermanson | Brian Lawrence | Dustin Hermanson | | 453 | 415 | 38 |
| 2004-07-29 | vs SFN | 102 | W 7-4 | 57-45 | 2 | 41,767 | Ismael Valdez | Brett Tomko | Blaine Neal | Brett Tomko | Trevor Hoffman | 460 | 419 | 41 |
| 2004-07-30 | vs LAN | 103 | L 3-12 | 57-46 | 2 | 42,552 | Adam Eaton | Jeff Weaver | Jeff Weaver | Adam Eaton | | 463 | 431 | 32 |
| 2004-07-31 | vs LAN | 104 | W 3-2 | 58-46 | 2 | 43,726 | Jake Peavy | Kazuhisa Ishii | Akinori Otsuka | Darren Dreifort | Trevor Hoffman | 466 | 433 | 33 |
| 2004-08-01 | vs LAN | 105 | L 1-2 | 58-47 | 2 | 44,056 | David Wells | Odalis Perez | Eric Gagne | Ricky Stone | Darren Dreifort | 467 | 435 | 32 |
| 2004-08-03 | vs PHI | 106 | L 2-5 | 58-48 | 2 | 37,134 | Brian Lawrence | Brett Myers | Brett Myers | Brian Lawrence | | 469 | 440 | 29 |
| 2004-08-04 | vs PHI | 107 | L 5-7 | 58-49 | 2 | 30,085 | Adam Eaton | Eric Milton | Eric Milton | Adam Eaton | Tim Worrell | 474 | 447 | 27 |
| 2004-08-05 | vs PHI | 108 | L 3-5 | 58-50 | 2 | 36,127 | Sterling Hitchcock | Kevin Millwood | Felix Rodriguez | Trevor Hoffman | Tim Worrell | 477 | 452 | 25 |
| 2004-08-06 | vs PIT | 109 | W 13-1 | 59-50 | 2 | 40,026 | Jake Peavy | Ryan Vogelsong | Jake Peavy | Ryan Vogelsong | | 490 | 453 | 37 |
| 2004-08-07 | vs PIT | 110 | L 1-3 | 59-51 | 2 | 40,681 | David Wells | Kip Wells | Kip Wells | David Wells | Jose Mesa | 491 | 456 | 35 |
| 2004-08-08 | vs PIT | 111 | L 2-4 | 59-52 | 2 | 39,742 | Brian Lawrence | Oliver Perez | Oliver Perez | Brian Lawrence | Jose Mesa | 493 | 460 | 33 |
| 2004-08-10 | @ CHN | 112 | W 8-6 | 60-52 | 2 | 39,097 | Adam Eaton | Mark Prior | Adam Eaton | Mark Prior | Trevor Hoffman | 501 | 466 | 35 |
| 2004-08-11 | @ CHN | 113 | L 1-5 | 60-53 | 2 | 39,165 | Sterling Hitchcock | Carlos Zambrano | Carlos Zambrano | Sterling Hitchcock | | 502 | 471 | 31 |
| 2004-08-12 | @ CHN | 114 | W 5-4 | 61-53 | 2 | 39,054 | Jake Peavy | Matt Clement | Ricky Stone | Ryan Dempster | Trevor Hoffman | 507 | 475 | 32 |
| 2004-08-13 | @ CIN | 115 | W 14-5 | 62-53 | 2 | 26,736 | David Wells | Paul Wilson | David Wells | Paul Wilson | Jay Witasick | 521 | 480 | 41 |
| 2004-08-14 | @ CIN | 116 | L 5-11 | 62-54 | 2 | 37,161 | Brian Lawrence | Jose Acevedo | Jose Acevedo | Brian Lawrence | | 526 | 491 | 35 |
| 2004-08-15 | @ CIN | 117 | W 7-2 | 63-54 | 2 | 31,447 | Adam Eaton | Luke Hudson | Adam Eaton | Luke Hudson | | 533 | 493 | 40 |
| 2004-08-16 | vs ATL | 118 | L 4-5 | 63-55 | 3 | 34,426 | Sterling Hitchcock | Mike Hampton | Mike Hampton | Sterling Hitchcock | John Smoltz | 537 | 498 | 39 |
| 2004-08-17 | vs ATL | 119 | W 11-6 | 64-55 | 3 | 36,184 | Jake Peavy | Jaret Wright | Jake Peavy | Jaret Wright | | 548 | 504 | 44 |
| 2004-08-18 | vs ATL | 120 | L 5-6 | 64-56 | 3 | 36,827 | David Wells | Paul Byrd | Chris Reitsma | Trevor Hoffman | John Smoltz | 553 | 510 | 43 |
| 2004-08-20 | vs FLO | 121 | W 6-1 | 65-56 | 3 | 38,389 | Brian Lawrence | Dontrelle Willis | Brian Lawrence | Dontrelle Willis | | 559 | 511 | 48 |
| 2004-08-21 | vs FLO | 122 | L 2-8 | 65-57 | 3 | 44,149 | Adam Eaton | Josh Beckett | Josh Beckett | Adam Eaton | | 561 | 519 | 42 |
| 2004-08-22 | vs FLO | 123 | L 3-8 | 65-58 | 3 | 40,019 | Sterling Hitchcock | Carl Pavano | Carl Pavano | Sterling Hitchcock | Guillermo Mota | 564 | 527 | 37 |
| 2004-08-23 | @ NYN | 124 | W 9-4 | 66-58 | 3 | 25,475 | Jake Peavy | Aaron Heilman | Jake Peavy | Aaron Heilman | | 573 | 531 | 42 |
| 2004-08-24 | @ NYN | 125 | W 3-1 | 67-58 | 3 | 25,558 | David Wells | Kris Benson | David Wells | Kris Benson | Trevor Hoffman | 576 | 532 | 44 |
| 2004-08-25 | @ NYN | 126 | W 4-0 | 68-58 | 3 | 28,067 | Brian Lawrence | Al Leiter | Brian Lawrence | Al Leiter | | 580 | 532 | 48 |
| 2004-08-26 | @ NYN | 127 | W 10-3 | 69-58 | 3 | 27,621 | Adam Eaton | Steve Trachsel | Adam Eaton | Steve Trachsel | | 590 | 535 | 55 |
| 2004-08-27 | @ MON | 128 | L 3-10 | 69-59 | 3 | 8,165 | Dennis Tankersley | Scott Downs | Scott Downs | Dennis Tankersley | | 593 | 545 | 48 |
| 2004-08-28 | @ MON | 129 | W 5-2 | 70-59 | 2 | 15,450 | Jake Peavy | John Patterson | Jake Peavy | John Patterson | Trevor Hoffman | 598 | 547 | 51 |
| 2004-08-29 | @ MON | 130 | W 11-3 | 71-59 | 2 | 12,181 | David Wells | Sun-Woo Kim | David Wells | Sun-Woo Kim | | 609 | 550 | 59 |
| 2004-08-31 | @ SLN | 131 | L 3-9 | 71-60 | 3 | 30,816 | Brian Lawrence | Woody Williams | Woody Williams | Brian Lawrence | | 612 | 559 | 53 |
| 2004-09-01 | @ SLN | 132 | L 2-4 | 71-61 | 3 | 32,390 | Adam Eaton | Chris Carpenter | Chris Carpenter | Adam Eaton | Jason Isringhausen | 614 | 563 | 51 |
| 2004-09-02 | @ SLN | 133 | L 2-7 | 71-62 | 3 | 32,785 | Jake Peavy | Jeff Suppan | Jeff Suppan | Jake Peavy | | 616 | 570 | 46 |
| 2004-09-03 | vs COL | 134 | W 7-6 | 72-62 | 3 | 35,555 | David Wells | Jason Jennings | Scott Linebrink | Scott Dohmann | Trevor Hoffman | 623 | 576 | 47 |
| 2004-09-04 | vs COL | 135 | L 2-8 | 72-63 | 3 | 42,716 | Dennis Tankersley | Shawn Estes | Shawn Estes | Dennis Tankersley | | 625 | 584 | 41 |
| 2004-09-05 | vs COL | 136 | L 2-5 | 72-64 | 3 | 33,272 | Brian Lawrence | Jeff Francis | Jeff Francis | Brian Lawrence | | 627 | 589 | 38 |
| 2004-09-06 | vs SLN | 137 | W 7-3 | 73-64 | 3 | 34,382 | Adam Eaton | Chris Carpenter | Scott Linebrink | Cal Eldred | Trevor Hoffman | 634 | 592 | 42 |
| 2004-09-07 | vs SLN | 138 | L 2-4 | 73-65 | 3 | 32,738 | Jake Peavy | Jeff Suppan | Jeff Suppan | Jake Peavy | Jason Isringhausen | 636 | 596 | 40 |
| 2004-09-08 | vs SLN | 139 | W 10-5 | 74-65 | 3 | 34,277 | David Wells | Matt Morris | David Wells | Matt Morris | | 646 | 601 | 45 |
| 2004-09-09 | @ COL | 140 | L 7-9 | 74-66 | 3 | 20,027 | Justin Germano | Jason Jennings | Javier Lopez | Scott Linebrink | Shawn Chacon | 653 | 610 | 43 |
| 2004-09-10 | @ COL | 141 | W 10-4 | 75-66 | 3 | 22,279 | Brian Lawrence | Shawn Estes | Brian Lawrence | Tim Harikkala | | 663 | 614 | 49 |
| 2004-09-11 | @ COL | 142 | L 2-13 | 75-67 | 3 | 22,684 | Adam Eaton | Jeff Francis | Jeff Francis | Adam Eaton | | 665 | 627 | 38 |
| 2004-09-12 | @ COL | 143 | W 15-2 | 76-67 | 3 | 21,608 | Jake Peavy | Jamey Wright | Jake Peavy | Steve Reed | | 680 | 629 | 51 |
| 2004-09-13 | @ LAN | 144 | W 9-7 | 77-67 | 3 | 36,050 | David Wells | Odalis Perez | David Wells | Odalis Perez | Trevor Hoffman | 689 | 636 | 53 |
| 2004-09-14 | @ LAN | 145 | L 3-6 | 77-68 | 3 | 29,704 | Justin Germano | Jose Lima | Jose Lima | Justin Germano | Eric Gagne | 692 | 642 | 50 |
| 2004-09-15 | @ LAN | 146 | W 7-3 | 78-68 | 3 | 34,105 | Brian Lawrence | Wilson Alvarez | Brian Lawrence | Wilson Alvarez | Trevor Hoffman | 699 | 645 | 54 |
| 2004-09-16 | @ LAN | 147 | W 3-0 | 79-68 | 3 | 43,185 | Adam Eaton | Jeff Weaver | Adam Eaton | Jeff Weaver | Trevor Hoffman | 702 | 645 | 57 |
| 2004-09-17 | @ SFN | 148 | L 1-4 | 79-69 | 3 | 42,526 | Jake Peavy | Noah Lowry | Noah Lowry | Jake Peavy | Dustin Hermanson | 703 | 649 | 54 |
| 2004-09-18 | @ SFN | 149 | W 5-1 | 80-69 | 3 | 42,515 | David Wells | Jason Schmidt | David Wells | Jason Schmidt | Trevor Hoffman | 708 | 650 | 58 |
| 2004-09-19 | @ SFN | 150 | L 2-4 | 80-70 | 3 | 41,428 | Brian Lawrence | Kirk Rueter | Dustin Hermanson | Scott Linebrink | | 710 | 654 | 56 |
| 2004-09-21 | vs LAN | 151 | W 9-4 | 81-70 | 3 | 39,428 | Adam Eaton | Jeff Weaver | Adam Eaton | Jeff Weaver | | 719 | 658 | 61 |
| 2004-09-22 | vs LAN | 152 | W 4-0 | 82-70 | 3 | 41,303 | Jake Peavy | Brad Penny | Jake Peavy | Brad Penny | | 723 | 658 | 65 |
| 2004-09-23 | vs LAN | 153 | L 6-9 | 82-71 | 3 | 42,159 | Brian Lawrence | Kazuhisa Ishii | Yhency Brazoban | Brian Lawrence | Eric Gagne | 729 | 667 | 62 |
| 2004-09-24 | vs ARI | 154 | W 6-5 | 83-71 | 3 | 36,927 | David Wells | Mike Gosling | Akinori Otsuka | Greg Aquino | | 735 | 672 | 63 |
| 2004-09-25 | vs ARI | 155 | W 6-5 | 84-71 | 3 | 44,863 | Adam Eaton | Steve Randolph | Antonio Osuna | Chad Durbin | Trevor Hoffman | 741 | 677 | 64 |
| 2004-09-26 | vs ARI | 156 | W 7-1 | 85-71 | 3 | 39,639 | Jake Peavy | Steve Sparks | Jake Peavy | Steve Sparks | | 748 | 678 | 70 |
| 2004-09-28 | vs SFN | 157 | L 5-7 | 85-72 | 3 | 35,529 | Brian Lawrence | Jason Schmidt | Jason Schmidt | Brian Lawrence | Dustin Hermanson | 753 | 685 | 68 |
| 2004-09-29 | vs SFN | 158 | W 4-3 | 86-72 | 3 | 38,398 | David Wells | Noah Lowry | Trevor Hoffman | Dustin Hermanson | | 757 | 688 | 69 |
| 2004-09-30 | vs SFN | 159 | L 1-4 | 86-73 | 3 | 45,389 | Adam Eaton | Jerome Williams | Jerome Williams | Adam Eaton | Dustin Hermanson | 758 | 692 | 66 |
| 2004-10-01 | @ ARI | 160 | W 3-2 | 87-73 | 3 | 25,929 | Jake Peavy | Mike Gosling | Jake Peavy | Mike Gosling | Trevor Hoffman | 761 | 694 | 67 |
| 2004-10-02 | @ ARI | 161 | L 6-7 | 87-74 | 3 | 30,733 | Brian Sweeney | Randy Johnson | Randy Johnson | Mike Bynum | Greg Aquino | 767 | 701 | 66 |
| 2004-10-03 | @ ARI | 162 | L 1-4 | 87-75 | 3 | 29,425 | David Wells | Brandon Webb | Brandon Webb | David Wells | Greg Aquino | 768 | 705 | 63 |