| 2004-04-06 | @ ARI | 1 | W 6-2 | 1-0 | 1 | 46,949 | Shawn Estes | Randy Johnson | Shawn Estes | Randy Johnson | | 6 | 2 | 4 |
| 2004-04-07 | @ ARI | 2 | L 5-9 | 1-1 | 4 | 25,918 | Jason Jennings | Brandon Webb | Brandon Webb | Jason Jennings | Matt Mantei | 11 | 11 | 0 |
| 2004-04-08 | @ ARI | 3 | L 5-6 | 1-2 | 5 | 26,448 | Joe Kennedy | Elmer Dessens | Steve Randolph | Shawn Chacon | | 16 | 17 | -1 |
| 2004-04-09 | @ LAN | 4 | L 1-5 | 1-3 | 5 | 54,599 | Scott Elarton | Kazuhisa Ishii | Kazuhisa Ishii | Scott Elarton | Wilson Alvarez | 17 | 22 | -5 |
| 2004-04-10 | @ LAN | 5 | L 4-7 | 1-4 | 5 | 35,318 | Denny Stark | Hideo Nomo | Hideo Nomo | Denny Stark | Eric Gagne | 21 | 29 | -8 |
| 2004-04-11 | @ LAN | 6 | W 4-2 | 2-4 | 5 | 27,076 | Shawn Estes | Odalis Perez | Shawn Estes | Odalis Perez | Shawn Chacon | 25 | 31 | -6 |
| 2004-04-12 | vs ARI | 7 | W 7-4 | 3-4 | 4 | 48,013 | Jason Jennings | Brandon Webb | Vladimir Nunez | Mike Koplove | Shawn Chacon | 32 | 35 | -3 |
| 2004-04-14 | vs ARI | 8 | W 14-4 | 4-4 | 3 | 23,128 | Joe Kennedy | Elmer Dessens | Joe Kennedy | Elmer Dessens | | 46 | 39 | 7 |
| 2004-04-15 | vs ARI | 9 | L 10-11 | 4-5 | 3 | 22,320 | Scott Elarton | Casey Daigle | Mike Koplove | Scott Elarton | Matt Mantei | 56 | 50 | 6 |
| 2004-04-16 | @ SLN | 10 | L 5-13 | 4-6 | 4 | 34,541 | Denny Stark | Matt Morris | Matt Morris | Denny Stark | | 61 | 63 | -2 |
| 2004-04-17 | @ SLN | 11 | L 4-8 | 4-7 | 5 | 46,471 | Shawn Estes | Jason Marquis | Jason Marquis | Shawn Estes | | 65 | 71 | -6 |
| 2004-04-18 | @ SLN | 12 | W 8-5 | 5-7 | 3 | 34,697 | Jason Jennings | Woody Williams | Jason Jennings | Woody Williams | Shawn Chacon | 73 | 76 | -3 |
| 2004-04-20 | vs LAN | 13 | W 7-1 | 6-7 | 3 | 22,169 | Joe Kennedy | Kazuhisa Ishii | Joe Kennedy | Kazuhisa Ishii | | 80 | 77 | 3 |
| 2004-04-21 | vs LAN | 14 | L 4-9 | 6-8 | 3 | 21,685 | Scott Elarton | Hideo Nomo | Hideo Nomo | Scott Elarton | | 84 | 86 | -2 |
| 2004-04-22 | vs LAN | 15 | W 7-1 | 7-8 | 3 | 19,667 | Shawn Estes | Jose Lima | Shawn Estes | Jose Lima | | 91 | 87 | 4 |
| 2004-04-23 | vs HOU | 16 | L 7-13 | 7-9 | 3 | 23,719 | Jason Jennings | Brandon Duckworth | Brandon Duckworth | Jason Jennings | | 98 | 100 | -2 |
| 2004-04-24 | vs HOU | 17 | L 5-8 | 7-10 | 3 | 35,260 | Jeff Fassero | Roger Clemens | Roger Clemens | Jeff Fassero | Octavio Dotel | 103 | 108 | -5 |
| 2004-04-25 | vs HOU | 18 | W 4-1 | 8-10 | 3 | 30,912 | Joe Kennedy | Wade Miller | Joe Kennedy | Wade Miller | Shawn Chacon | 107 | 109 | -2 |
| 2004-04-26 | vs FLO | 19 | L 3-6 | 8-11 | 4 | 20,009 | Scott Elarton | Carl Pavano | Carl Pavano | Scott Elarton | Armando Benitez | 110 | 115 | -5 |
| 2004-04-27 | vs FLO | 20 | W 13-10 | 9-11 | 4 | 20,615 | Shawn Estes | Darren Oliver | Vladimir Nunez | Chad Fox | Shawn Chacon | 123 | 125 | -2 |
| 2004-04-28 | vs FLO | 21 | L 4-9 | 9-12 | 4 | 27,402 | Jason Jennings | Josh Beckett | Josh Beckett | Jason Jennings | | 127 | 134 | -7 |
| 2004-05-01 | vs ATL | 22 | W 3-2 | 10-13 | 5 | 30,176 | Joe Kennedy | Mike Hampton | Vladimir Nunez | Chris Reitsma | Shawn Chacon | 130 | 136 | -6 |
| 2004-05-01 | vs ATL | 23 | L 7-11 | 10-13 | 5 | 24,272 | Scott Elarton | John Thomson | C.J. Nitkowski | Vladimir Nunez | | 137 | 147 | -10 |
| 2004-05-02 | vs ATL | 24 | W 13-4 | 11-13 | 4 | 35,234 | Shawn Estes | Horacio Ramirez | Shawn Estes | Horacio Ramirez | | 150 | 151 | -1 |
| 2004-05-04 | @ MON | 25 | L 4-10 | 11-14 | 5 | 4,001 | Jason Jennings | Claudio Vargas | Claudio Vargas | Jason Jennings | | 154 | 161 | -7 |
| 2004-05-05 | @ MON | 26 | W 2-0 | 12-14 | 4 | 3,609 | Joe Kennedy | Zach Day | Joe Kennedy | Zach Day | Shawn Chacon | 156 | 161 | -5 |
| 2004-05-06 | @ MON | 27 | L 1-3 | 12-15 | 4 | 8,851 | Scott Elarton | Livan Hernandez | Livan Hernandez | Scott Elarton | | 157 | 164 | -7 |
| 2004-05-07 | @ CHN | 28 | L 0-11 | 12-16 | 5 | 37,307 | Shawn Estes | Carlos Zambrano | Carlos Zambrano | Shawn Estes | | 157 | 175 | -18 |
| 2004-05-08 | @ CHN | 29 | W 4-3 | 13-16 | 3 | 39,546 | Jason Jennings | Greg Maddux | Jason Jennings | Greg Maddux | Shawn Chacon | 161 | 178 | -17 |
| 2004-05-09 | @ CHN | 30 | L 4-5 | 13-17 | 4 | 39,155 | Joe Kennedy | Sergio Mitre | Glendon Rusch | Jeff Fassero | | 165 | 183 | -18 |
| 2004-05-11 | vs PIT | 31 | L 10-15 | 13-18 | 5 | 21,123 | Scott Elarton | Kip Wells | Salomon Torres | Javier Lopez | | 175 | 198 | -23 |
| 2004-05-13 | vs PIT | 32 | W 7-5 | 14-19 | 4 | 0 | Shawn Estes | Kris Benson | Shawn Estes | Kris Benson | Shawn Chacon | 182 | 203 | -21 |
| 2004-05-13 | vs PIT | 33 | L 2-11 | 14-19 | 4 | 20,041 | Jason Jennings | Oliver Perez | Oliver Perez | Jason Jennings | | 184 | 214 | -30 |
| 2004-05-14 | vs PHI | 34 | L 4-6 | 14-20 | 4 | 32,171 | Joe Kennedy | Eric Milton | Eric Milton | Joe Kennedy | Tim Worrell | 188 | 220 | -32 |
| 2004-05-15 | vs PHI | 35 | L 5-16 | 14-21 | 4 | 33,629 | Scott Elarton | Brett Myers | Brett Myers | Scott Elarton | | 193 | 236 | -43 |
| 2004-05-16 | vs PHI | 36 | W 7-6 | 15-21 | 3 | 33,623 | Jason Young | Kevin Millwood | Tim Harikkala | Rheal Cormier | Shawn Chacon | 200 | 242 | -42 |
| 2004-05-17 | vs PHI | 37 | W 7-6 | 16-21 | 3 | 22,111 | Aaron Cook | Randy Wolf | Brian Fuentes | Tim Worrell | | 207 | 248 | -41 |
| 2004-05-18 | @ CIN | 38 | W 8-3 | 17-21 | 3 | 17,389 | Shawn Estes | Cory Lidle | Shawn Estes | Cory Lidle | | 215 | 251 | -36 |
| 2004-05-19 | @ CIN | 39 | L 3-4 | 17-22 | 3 | 16,410 | Jason Jennings | Jose Acevedo | John Riedling | Brian Fuentes | | 218 | 255 | -37 |
| 2004-05-20 | @ CIN | 40 | L 1-3 | 17-23 | 3 | 21,576 | Joe Kennedy | Paul Wilson | Paul Wilson | Joe Kennedy | Danny Graves | 219 | 258 | -39 |
| 2004-05-21 | @ NYN | 41 | L 7-9 | 17-24 | 4 | 20,148 | Jason Young | Matt Ginter | Matt Ginter | Jason Young | | 226 | 267 | -41 |
| 2004-05-22 | @ NYN | 42 | L 4-5 | 17-25 | 4 | 27,526 | Aaron Cook | Tyler Yates | David Weathers | Vladimir Nunez | Braden Looper | 230 | 272 | -42 |
| 2004-05-23 | @ NYN | 43 | L 0-4 | 17-26 | 5 | 37,486 | Shawn Estes | Tom Glavine | Tom Glavine | Shawn Estes | | 230 | 276 | -46 |
| 2004-05-25 | vs SDN | 44 | L 6-11 | 17-27 | 4 | 33,799 | Joe Kennedy | Ismael Valdez | Scott Linebrink | Jeff Fassero | | 236 | 287 | -51 |
| 2004-05-26 | vs SDN | 45 | W 13-6 | 18-27 | 4 | 28,129 | Jason Jennings | Adam Eaton | Jason Jennings | Adam Eaton | | 249 | 293 | -44 |
| 2004-05-27 | vs SDN | 46 | L 3-4 | 18-28 | 4 | 24,543 | Aaron Cook | Justin Germano | Akinori Otsuka | Vladimir Nunez | Trevor Hoffman | 252 | 297 | -45 |
| 2004-05-28 | @ SFN | 47 | L 2-4 | 18-29 | 4 | 39,983 | Shawn Estes | Brett Tomko | Jim Brower | Shawn Chacon | | 254 | 301 | -47 |
| 2004-05-29 | @ SFN | 48 | L 3-5 | 18-30 | 4 | 42,297 | Jeff Fassero | Jerome Williams | Jerome Williams | Jeff Fassero | Matt Herges | 257 | 306 | -49 |
| 2004-05-30 | @ SFN | 49 | L 1-3 | 18-31 | 4 | 42,463 | Joe Kennedy | Jason Schmidt | Jason Schmidt | Joe Kennedy | Matt Herges | 258 | 309 | -51 |
| 2004-05-31 | @ SDN | 50 | W 7-1 | 19-31 | 4 | 38,355 | Jason Jennings | Adam Eaton | Jason Jennings | Adam Eaton | | 265 | 310 | -45 |
| 2004-06-01 | @ SDN | 51 | W 7-1 | 20-31 | 4 | 28,313 | Aaron Cook | Justin Germano | Aaron Cook | Justin Germano | | 272 | 311 | -39 |
| 2004-06-02 | @ SDN | 52 | L 1-2 | 20-32 | 4 | 38,521 | Shawn Estes | Brian Lawrence | Trevor Hoffman | Brian Fuentes | | 273 | 313 | -40 |
| 2004-06-04 | vs SFN | 53 | L 7-13 | 20-33 | 5 | 32,093 | Joe Kennedy | Jason Schmidt | Jason Schmidt | Jeff Fassero | | 280 | 326 | -46 |
| 2004-06-05 | vs SFN | 54 | W 11-2 | 21-33 | 4 | 30,149 | Jason Jennings | Kirk Rueter | Jason Jennings | Kirk Rueter | | 291 | 328 | -37 |
| 2004-06-06 | vs SFN | 55 | L 4-16 | 21-34 | 5 | 37,147 | Aaron Cook | Dustin Hermanson | Dustin Hermanson | Aaron Cook | | 295 | 344 | -49 |
| 2004-06-07 | vs SFN | 56 | L 5-10 | 21-35 | 5 | 20,887 | Shawn Estes | Brett Tomko | Jim Brower | Steve Reed | | 300 | 354 | -54 |
| 2004-06-08 | @ NYA | 57 | L 1-2 | 21-36 | 5 | 51,852 | Jeff Fassero | Javier Vazquez | Javier Vazquez | Jeff Fassero | Mariano Rivera | 301 | 356 | -55 |
| 2004-06-09 | @ NYA | 58 | L 5-7 | 21-37 | 5 | 38,013 | Joe Kennedy | Kevin Brown | Paul Quantrill | Joe Kennedy | Mariano Rivera | 306 | 363 | -57 |
| 2004-06-10 | @ NYA | 59 | L 4-10 | 21-38 | 5 | 41,586 | Jason Jennings | Jose Contreras | Jose Contreras | Jason Jennings | | 310 | 373 | -63 |
| 2004-06-11 | @ TBA | 60 | L 7-8 | 21-39 | 5 | 9,280 | Aaron Cook | Chad Gaudin | Danys Baez | Shawn Chacon | | 317 | 381 | -64 |
| 2004-06-12 | @ TBA | 61 | L 7-10 | 21-40 | 5 | 11,299 | Shawn Estes | Rob Bell | John Halama | Tim Harikkala | | 324 | 391 | -67 |
| 2004-06-13 | @ TBA | 62 | L 2-3 | 21-41 | 5 | 11,227 | Jeff Fassero | Dewon Brazelton | Jesus Colome | Shawn Chacon | | 326 | 394 | -68 |
| 2004-06-15 | vs BOS | 63 | W 6-3 | 22-41 | 5 | 40,489 | Joe Kennedy | Bronson Arroyo | Joe Kennedy | Bronson Arroyo | Shawn Chacon | 332 | 397 | -65 |
| 2004-06-16 | vs BOS | 64 | W 7-6 | 23-41 | 5 | 39,319 | Jason Jennings | Curt Schilling | Jason Jennings | Curt Schilling | Shawn Chacon | 339 | 403 | -64 |
| 2004-06-17 | vs BOS | 65 | L 0-11 | 23-42 | 5 | 40,088 | Aaron Cook | Derek Lowe | Derek Lowe | Aaron Cook | | 339 | 414 | -75 |
| 2004-06-18 | vs BAL | 66 | W 5-3 | 24-42 | 5 | 30,148 | Shawn Estes | Sidney Ponson | Shawn Estes | Sidney Ponson | Shawn Chacon | 344 | 417 | -73 |
| 2004-06-19 | vs BAL | 67 | W 11-6 | 25-42 | 5 | 33,326 | Jeff Fassero | Eric DuBose | Jeff Fassero | Eric DuBose | | 355 | 423 | -68 |
| 2004-06-20 | vs BAL | 68 | L 2-4 | 25-43 | 5 | 40,532 | Joe Kennedy | Daniel Cabrera | B.J. Ryan | Shawn Chacon | Jorge Julio | 357 | 427 | -70 |
| 2004-06-22 | @ MIL | 69 | L 2-6 | 25-44 | 5 | 13,264 | Jason Jennings | Doug Davis | Doug Davis | Javier Lopez | | 359 | 433 | -74 |
| 2004-06-23 | @ MIL | 70 | W 3-2 | 26-44 | 5 | 19,964 | Shawn Estes | Chris Capuano | Shawn Estes | Chris Capuano | Shawn Chacon | 362 | 435 | -73 |
| 2004-06-24 | @ MIL | 71 | W 3-0 | 27-44 | 4 | 21,224 | Aaron Cook | Ben Sheets | Aaron Cook | Ben Sheets | Shawn Chacon | 365 | 435 | -70 |
| 2004-06-25 | @ CLE | 72 | W 10-8 | 28-44 | 4 | 22,642 | Jeff Fassero | Jason Davis | Steve Reed | Jose Jimenez | Shawn Chacon | 375 | 443 | -68 |
| 2004-06-26 | @ CLE | 73 | L 3-4 | 28-45 | 4 | 29,124 | Joe Kennedy | CC Sabathia | Jeriome Robertson | Steve Reed | | 378 | 447 | -69 |
| 2004-06-27 | @ CLE | 74 | L 3-5 | 28-46 | 4 | 27,252 | Jason Jennings | Scott Elarton | Matt Miller | Jason Jennings | Jose Jimenez | 381 | 452 | -71 |
| 2004-06-29 | vs MIL | 75 | L 3-6 | 28-47 | 4 | 28,085 | Shawn Estes | Chris Capuano | Chris Capuano | Shawn Estes | Danny Kolb | 384 | 458 | -74 |
| 2004-06-30 | vs MIL | 76 | L 4-5 | 28-48 | 4 | 24,126 | Aaron Cook | Ben Sheets | Ben Sheets | Aaron Cook | Danny Kolb | 388 | 463 | -75 |
| 2004-07-01 | vs MIL | 77 | L 9-10 | 28-49 | 5 | 24,360 | Denny Stark | Victor Santos | Victor Santos | Denny Stark | Danny Kolb | 397 | 473 | -76 |
| 2004-07-02 | vs DET | 78 | W 9-8 | 29-49 | 4 | 47,585 | Joe Kennedy | Jeremy Bonderman | Shawn Chacon | Jamie Walker | | 406 | 481 | -75 |
| 2004-07-03 | vs DET | 79 | W 11-6 | 30-49 | 4 | 48,131 | Jason Jennings | Mike Maroth | Jason Jennings | Mike Maroth | | 417 | 487 | -70 |
| 2004-07-04 | vs DET | 80 | W 10-8 | 31-49 | 4 | 26,944 | Shawn Estes | Gary Knotts | Adam Bernero | Gary Knotts | Shawn Chacon | 427 | 495 | -68 |
| 2004-07-05 | @ SFN | 81 | W 7-4 | 32-49 | 4 | 39,977 | Aaron Cook | Brett Tomko | Aaron Cook | Brett Tomko | Shawn Chacon | 434 | 499 | -65 |
| 2004-07-06 | @ SFN | 82 | W 8-6 | 33-49 | 4 | 35,460 | Denny Stark | Jason Schmidt | Tim Harikkala | Jason Christiansen | Shawn Chacon | 442 | 505 | -63 |
| 2004-07-07 | @ SFN | 83 | L 4-8 | 33-50 | 4 | 35,673 | Adam Bernero | Kirk Rueter | Kirk Rueter | Adam Bernero | | 446 | 513 | -67 |
| 2004-07-08 | @ SDN | 84 | W 5-1 | 34-50 | 4 | 32,403 | Jason Jennings | Adam Eaton | Jason Jennings | Adam Eaton | | 451 | 514 | -63 |
| 2004-07-09 | @ SDN | 85 | W 6-5 | 35-50 | 4 | 41,168 | Shawn Estes | David Wells | Tim Harikkala | Trevor Hoffman | Shawn Chacon | 457 | 519 | -62 |
| 2004-07-10 | @ SDN | 86 | W 6-2 | 36-50 | 4 | 37,644 | Aaron Cook | Brian Lawrence | Aaron Cook | Brian Lawrence | | 463 | 521 | -58 |
| 2004-07-11 | @ SDN | 87 | L 2-4 | 36-51 | 4 | 41,188 | Denny Stark | Ismael Valdez | Ismael Valdez | Denny Stark | Trevor Hoffman | 465 | 525 | -60 |
| 2004-07-15 | vs SFN | 88 | L 5-7 | 36-52 | 4 | 30,159 | Jason Jennings | Jerome Williams | Jim Brower | Shawn Chacon | Scott Eyre | 470 | 532 | -62 |
| 2004-07-16 | vs SFN | 89 | W 7-1 | 37-52 | 4 | 31,583 | Shawn Estes | Kirk Rueter | Shawn Estes | Kirk Rueter | | 477 | 533 | -56 |
| 2004-07-17 | vs SFN | 90 | L 0-4 | 37-53 | 4 | 41,450 | Aaron Cook | Jason Schmidt | Jason Schmidt | Aaron Cook | | 477 | 537 | -60 |
| 2004-07-18 | vs SFN | 91 | W 10-9 | 38-53 | 4 | 35,032 | Adam Bernero | Dustin Hermanson | Tim Harikkala | Matt Herges | | 487 | 546 | -59 |
| 2004-07-19 | vs SDN | 92 | L 6-13 | 38-54 | 4 | 25,530 | Denny Stark | Ismael Valdez | Ismael Valdez | Denny Stark | | 493 | 559 | -66 |
| 2004-07-20 | vs SDN | 93 | L 7-9 | 38-55 | 4 | 26,770 | Jason Jennings | Adam Eaton | Adam Eaton | Jason Jennings | Trevor Hoffman | 500 | 568 | -68 |
| 2004-07-21 | @ LAN | 94 | W 6-5 | 39-55 | 4 | 34,343 | Shawn Estes | Kazuhisa Ishii | Shawn Estes | Kazuhisa Ishii | Shawn Chacon | 506 | 573 | -67 |
| 2004-07-22 | @ LAN | 95 | L 2-4 | 39-56 | 4 | 34,276 | Aaron Cook | Odalis Perez | Guillermo Mota | Tim Harikkala | Eric Gagne | 508 | 577 | -69 |
| 2004-07-23 | @ ARI | 96 | W 8-2 | 40-56 | 4 | 26,350 | Jeff Fassero | Casey Fossum | Jeff Fassero | Casey Fossum | | 516 | 579 | -63 |
| 2004-07-24 | @ ARI | 97 | W 8-2 | 41-56 | 4 | 31,409 | Jamey Wright | Lance Cormier | Jamey Wright | Lance Cormier | | 524 | 581 | -57 |
| 2004-07-25 | @ ARI | 98 | W 3-2 | 42-56 | 4 | 29,298 | Jason Jennings | Randy Johnson | Jason Jennings | Randy Choate | Shawn Chacon | 527 | 583 | -56 |
| 2004-07-26 | vs LAN | 99 | L 7-9 | 42-57 | 4 | 24,725 | Shawn Estes | Kazuhisa Ishii | Duaner Sanchez | Allan Simpson | Eric Gagne | 534 | 592 | -58 |
| 2004-07-27 | vs LAN | 100 | W 7-2 | 43-57 | 4 | 27,934 | Aaron Cook | Odalis Perez | Aaron Cook | Odalis Perez | | 541 | 594 | -53 |
| 2004-07-28 | vs LAN | 101 | W 5-4 | 44-57 | 4 | 25,492 | Jeff Fassero | Jose Lima | Steve Reed | Guillermo Mota | Shawn Chacon | 546 | 598 | -52 |
| 2004-07-29 | vs LAN | 102 | L 2-3 | 44-58 | 4 | 28,472 | Jamey Wright | Wilson Alvarez | Wilson Alvarez | Scott Dohmann | Eric Gagne | 548 | 601 | -53 |
| 2004-07-30 | vs ARI | 103 | W 4-1 | 45-58 | 4 | 29,436 | Jason Jennings | Randy Johnson | Jason Jennings | Randy Johnson | Shawn Chacon | 552 | 602 | -50 |
| 2004-07-31 | vs ARI | 104 | W 8-4 | 46-58 | 4 | 32,392 | Shawn Estes | Brandon Webb | Shawn Estes | Brandon Webb | Shawn Chacon | 560 | 606 | -46 |
| 2004-08-01 | vs ARI | 105 | W 10-2 | 47-58 | 4 | 24,193 | Aaron Cook | Edgar Gonzalez | Aaron Cook | Edgar Gonzalez | | 570 | 608 | -38 |
| 2004-08-03 | vs CHN | 106 | L 3-5 | 47-59 | 4 | 40,716 | Jeff Fassero | Kerry Wood | Kerry Wood | Jeff Fassero | LaTroy Hawkins | 573 | 613 | -40 |
| 2004-08-04 | vs CHN | 107 | L 8-11 | 47-60 | 4 | 45,305 | Jamey Wright | Carlos Zambrano | Kyle Farnsworth | Shawn Chacon | | 581 | 624 | -43 |
| 2004-08-05 | vs CHN | 108 | L 1-5 | 47-61 | 4 | 38,195 | Jason Jennings | Mark Prior | Mark Prior | Jason Jennings | Glendon Rusch | 582 | 629 | -47 |
| 2004-08-06 | vs CIN | 109 | W 8-5 | 48-61 | 4 | 26,187 | Shawn Estes | Brandon Claussen | Shawn Estes | Brandon Claussen | Shawn Chacon | 590 | 634 | -44 |
| 2004-08-07 | vs CIN | 110 | W 9-5 | 49-61 | 4 | 33,649 | Aaron Cook | Paul Wilson | Allan Simpson | Paul Wilson | | 599 | 639 | -40 |
| 2004-08-08 | vs CIN | 111 | L 7-14 | 49-62 | 4 | 28,721 | Jeff Fassero | Cory Lidle | Cory Lidle | Jeff Fassero | | 606 | 653 | -47 |
| 2004-08-09 | @ PHI | 112 | W 4-2 | 50-62 | 4 | 42,031 | Jamey Wright | Eric Milton | Tim Harikkala | Todd Jones | Shawn Chacon | 610 | 655 | -45 |
| 2004-08-10 | @ PHI | 113 | W 5-4 | 51-62 | 4 | 36,636 | Joe Kennedy | Vicente Padilla | Steve Reed | Tim Worrell | Shawn Chacon | 615 | 659 | -44 |
| 2004-08-11 | @ PHI | 114 | L 4-15 | 51-63 | 4 | 40,634 | Jason Jennings | Randy Wolf | Randy Wolf | Jason Jennings | | 619 | 674 | -55 |
| 2004-08-12 | @ PHI | 115 | W 3-1 | 52-63 | 4 | 37,464 | Shawn Estes | Cory Lidle | Shawn Estes | Cory Lidle | Shawn Chacon | 622 | 675 | -53 |
| 2004-08-13 | @ PIT | 116 | W 9-3 | 53-63 | 4 | 27,522 | Jeff Fassero | Kip Wells | Jeff Fassero | Kip Wells | | 631 | 678 | -47 |
| 2004-08-14 | @ PIT | 117 | L 1-6 | 53-64 | 4 | 37,312 | Jamey Wright | Oliver Perez | Oliver Perez | Jamey Wright | | 632 | 684 | -52 |
| 2004-08-15 | @ PIT | 118 | L 0-3 | 53-65 | 4 | 24,862 | Joe Kennedy | Josh Fogg | Josh Fogg | Joe Kennedy | Jose Mesa | 632 | 687 | -55 |
| 2004-08-17 | vs NYN | 119 | W 6-4 | 54-65 | 4 | 34,387 | Jason Jennings | Victor Zambrano | Jason Jennings | Dan Wheeler | Shawn Chacon | 638 | 691 | -53 |
| 2004-08-19 | vs NYN | 120 | L 3-10 | 54-67 | 4 | 30,827 | Shawn Estes | Kris Benson | Kris Benson | Shawn Estes | | 641 | 701 | -60 |
| 2004-08-19 | vs NYN | 121 | L 2-4 | 54-67 | 4 | 29,918 | Jeff Fassero | Al Leiter | Mike Stanton | Steve Reed | | 643 | 705 | -62 |
| 2004-08-20 | vs MON | 122 | L 3-4 | 54-68 | 4 | 32,707 | Jamey Wright | Tony Armas | Luis Ayala | Brian Fuentes | Chad Cordero | 646 | 709 | -63 |
| 2004-08-21 | vs MON | 123 | W 5-2 | 55-68 | 4 | 33,225 | Joe Kennedy | Livan Hernandez | Joe Kennedy | Livan Hernandez | | 651 | 711 | -60 |
| 2004-08-22 | vs MON | 124 | L 2-8 | 55-69 | 4 | 26,833 | Jason Jennings | John Patterson | John Patterson | Jason Jennings | | 653 | 719 | -66 |
| 2004-08-24 | @ ATL | 125 | L 5-6 | 55-70 | 4 | 27,914 | Shawn Estes | Russ Ortiz | Kevin Gryboski | Tim Harikkala | John Smoltz | 658 | 725 | -67 |
| 2004-08-25 | @ ATL | 126 | L 1-8 | 55-71 | 4 | 25,534 | Jeff Francis | John Thomson | John Thomson | Jeff Francis | | 659 | 733 | -74 |
| 2004-08-26 | @ ATL | 127 | L 4-6 | 55-72 | 4 | 28,360 | Jamey Wright | Mike Hampton | Mike Hampton | Jamey Wright | John Smoltz | 663 | 739 | -76 |
| 2004-08-27 | @ FLO | 128 | L 0-3 | 55-73 | 4 | 26,735 | Joe Kennedy | Ismael Valdez | Ismael Valdez | Joe Kennedy | Armando Benitez | 663 | 742 | -79 |
| 2004-08-28 | @ FLO | 129 | L 3-4 | 55-74 | 4 | 35,243 | Jason Jennings | Carl Pavano | Carl Pavano | Steve Reed | Armando Benitez | 666 | 746 | -80 |
| 2004-08-29 | @ FLO | 130 | L 4-8 | 55-75 | 4 | 39,104 | Shawn Estes | A.J. Burnett | A.J. Burnett | Shawn Estes | | 670 | 754 | -84 |
| 2004-08-31 | @ SFN | 131 | L 5-9 | 55-76 | 4 | 38,305 | Jeff Francis | Brett Tomko | Brett Tomko | Jeff Francis | Dustin Hermanson | 675 | 763 | -88 |
| 2004-09-01 | @ SFN | 132 | W 4-1 | 56-76 | 4 | 36,024 | Jamey Wright | Kirk Rueter | Jamey Wright | Kirk Rueter | Shawn Chacon | 679 | 764 | -85 |
| 2004-09-02 | @ SFN | 133 | W 6-5 | 57-76 | 4 | 36,971 | Joe Kennedy | Jason Schmidt | Joe Kennedy | Jason Schmidt | Shawn Chacon | 685 | 769 | -84 |
| 2004-09-03 | @ SDN | 134 | L 6-7 | 57-77 | 4 | 35,555 | Jason Jennings | David Wells | Scott Linebrink | Scott Dohmann | Trevor Hoffman | 691 | 776 | -85 |
| 2004-09-04 | @ SDN | 135 | W 8-2 | 58-77 | 4 | 42,716 | Shawn Estes | Dennis Tankersley | Shawn Estes | Dennis Tankersley | | 699 | 778 | -79 |
| 2004-09-05 | @ SDN | 136 | W 5-2 | 59-77 | 4 | 33,272 | Jeff Francis | Brian Lawrence | Jeff Francis | Brian Lawrence | | 704 | 780 | -76 |
| 2004-09-07 | vs SFN | 137 | W 8-7 | 60-77 | 4 | 30,803 | Jamey Wright | Jason Schmidt | Tim Harikkala | Jason Christiansen | Shawn Chacon | 712 | 787 | -75 |
| 2004-09-08 | vs SFN | 138 | L 3-5 | 60-78 | 4 | 24,700 | Joe Kennedy | Kirk Rueter | Tyler Walker | Steve Reed | Dustin Hermanson | 715 | 792 | -77 |
| 2004-09-09 | vs SDN | 139 | W 9-7 | 61-78 | 4 | 20,027 | Jason Jennings | Justin Germano | Javier Lopez | Scott Linebrink | Shawn Chacon | 724 | 799 | -75 |
| 2004-09-10 | vs SDN | 140 | L 4-10 | 61-79 | 4 | 22,279 | Shawn Estes | Brian Lawrence | Brian Lawrence | Tim Harikkala | | 728 | 809 | -81 |
| 2004-09-11 | vs SDN | 141 | W 13-2 | 62-79 | 4 | 22,684 | Jeff Francis | Adam Eaton | Jeff Francis | Adam Eaton | | 741 | 811 | -70 |
| 2004-09-12 | vs SDN | 142 | L 2-15 | 62-80 | 4 | 21,608 | Jamey Wright | Jake Peavy | Jake Peavy | Steve Reed | | 743 | 826 | -83 |
| 2004-09-13 | @ ARI | 143 | W 9-2 | 63-80 | 4 | 22,070 | Joe Kennedy | Casey Fossum | Joe Kennedy | Casey Fossum | | 752 | 828 | -76 |
| 2004-09-14 | @ ARI | 144 | L 3-4 | 63-81 | 4 | 23,175 | Jason Jennings | Mike Gosling | Randy Choate | Steve Reed | | 755 | 832 | -77 |
| 2004-09-15 | @ ARI | 145 | L 2-3 | 63-82 | 4 | 22,598 | Shawn Estes | Randy Johnson | Randy Johnson | Shawn Estes | Greg Aquino | 757 | 835 | -78 |
| 2004-09-16 | @ ARI | 146 | L 5-8 | 63-83 | 4 | 22,281 | Jeff Francis | Steve Randolph | Chad Durbin | Scott Dohmann | Mike Fetters | 762 | 843 | -81 |
| 2004-09-17 | vs LAN | 147 | L 6-8 | 63-84 | 4 | 23,572 | Jamey Wright | Hideo Nomo | Eric Gagne | Shawn Chacon | | 768 | 851 | -83 |
| 2004-09-18 | vs LAN | 148 | W 8-1 | 64-84 | 4 | 21,664 | Joe Kennedy | Odalis Perez | Joe Kennedy | Odalis Perez | | 776 | 852 | -76 |
| 2004-09-19 | vs LAN | 149 | L 6-7 | 64-85 | 4 | 27,175 | Jason Jennings | Edwin Jackson | Yhency Brazoban | Shawn Chacon | Eric Gagne | 782 | 859 | -77 |
| 2004-09-22 | vs ARI | 150 | W 4-2 | 65-85 | 4 | 20,125 | Shawn Estes | Randy Johnson | Shawn Estes | Randy Johnson | Shawn Chacon | 786 | 861 | -75 |
| 2004-09-23 | vs ARI | 151 | W 7-1 | 67-85 | 4 | 0 | Jeff Francis | Brandon Webb | Jeff Francis | Brandon Webb | | 793 | 862 | -69 |
| 2004-09-23 | vs ARI | 152 | W 2-1 | 67-85 | 4 | 20,765 | Jamey Wright | Casey Fossum | Allan Simpson | Randy Choate | | 795 | 863 | -68 |
| 2004-09-24 | vs SLN | 153 | L 4-5 | 67-86 | 4 | 45,053 | Jason Jennings | Jeff Suppan | Jeff Suppan | Jason Jennings | Kiko Calero | 799 | 868 | -69 |
| 2004-09-25 | vs SLN | 154 | L 6-10 | 67-87 | 4 | 29,751 | Joe Kennedy | Alberto Reyes | Randy Flores | Tim Harikkala | Jason Isringhausen | 805 | 878 | -73 |
| 2004-09-26 | vs SLN | 155 | L 3-9 | 67-88 | 4 | 26,866 | Chris Gissell | Jason Marquis | Jason Marquis | Chris Gissell | Cal Eldred | 808 | 887 | -79 |
| 2004-09-27 | @ LAN | 156 | L 7-8 | 67-89 | 4 | 36,958 | Shawn Estes | Edwin Jackson | Yhency Brazoban | Steve Reed | | 815 | 895 | -80 |
| 2004-09-28 | @ LAN | 157 | L 4-5 | 67-90 | 4 | 33,588 | Jamey Wright | Kazuhisa Ishii | Elmer Dessens | Tim Harikkala | | 819 | 900 | -81 |
| 2004-09-29 | @ LAN | 158 | W 4-1 | 68-90 | 4 | 43,304 | Jeff Francis | Odalis Perez | Brian Fuentes | Yhency Brazoban | Chin-hui Tsao | 823 | 901 | -78 |
| 2004-09-30 | @ LAN | 159 | L 2-4 | 68-91 | 4 | 53,438 | Jason Jennings | Jose Lima | Yhency Brazoban | Brian Fuentes | | 825 | 905 | -80 |
| 2004-10-01 | @ HOU | 160 | L 2-4 | 68-92 | 4 | 41,717 | Joe Kennedy | Peter Munro | Mike Gallo | Joe Kennedy | Brad Lidge | 827 | 909 | -82 |
| 2004-10-02 | @ HOU | 161 | L 3-9 | 68-93 | 4 | 43,279 | Shawn Estes | Roy Oswalt | Roy Oswalt | Shawn Estes | | 830 | 918 | -88 |
| 2004-10-03 | @ HOU | 162 | L 3-5 | 68-94 | 4 | 43,082 | Jamey Wright | Brandon Backe | Brandon Backe | Jamey Wright | Brad Lidge | 833 | 923 | -90 |