The men's marathon event at the 2003 Pan American Games took place on Saturday, 9 August 2003. Brazil's title defender Vanderlei de Lima once again proved to be the best marathoner, clocking a winning time of 2h 19m 08s.
Medalists edit
| Gold | Vanderlei de Lima Brazil
|
| Silver | Bruce Deacon Canada
|
| Bronze | Diego Colorado Colombia
|
Records edit
| World record |  Khalid Khannouchi (USA) |
2:05:38 | 14 April 2002 |  London, Great Britain
|
| Pan Am record |  Jorge González (PUR) |
2:12:43 | 28 August 1983 |  Caracas, Venezuela
|
Results edit
| Rank | Athlete | Time |
|---|---|---|
| 1 | Vanderlei de Lima (BRA) |
2:19:08 |
| 2 |  Bruce Deacon (CAN) |
2:20:25 |
| 3 |  Diego Colorado (COL) |
2:21:48 |
| 4 |  Aguelmis Rojas (CUB) |
2:23:18 |
| 5 |  Francisco Bautista (MEX) |
2:25:50 |
| 6 |  Daniel Simbrón (ARG) |
2:28:21 |
| 7 |  Pamenos Ballantyne (VIN) |
2:29:37 |
| 8 |  Chris Banks (USA) |
2:32:22 |
| 9 | Hugo Jiménez (COL) |
2:35:26 |
| 10 | Jeff Campbell (USA) |
2:36:31 |
| 11 |  Cristian Villavicencio (NCA) |
2:37:28 |
| 12 |  Larry Alberto Sánchez (VEN) |
2:42:02 |
| 13 |  José Francisco Paulino (DOM) |
2:43:11 |
| — |  Silvio Guerra (ECU) |
DNF |
| — | Genílson da Silva (BRA) |
DNF |
| — | Bernardo Jiménez (DOM) |
DNF |
| — |  Alfredo Arévalo (GUA) |
DNF |
| — | Luis Fonseca (VEN) |
DNF |
| — | Benjamín Paredes (MEX) |
DNF |