Swimming at the 2005 World Aquatics Championships – Men's 400 metre individual medley
# Swimming at the 2005 World Aquatics Championships – Men's 400 metre individual medley

The Men's 400m Individual Medley (or "I.M.") event at the 2005 FINA World Aquatics Championships was swum on 31 July 2005 in Montreal, Quebec, Canada. Preliminary heats were held in the day's morning session, with the top-8 finishers advancing to swim again in the event's final that evening.

Prior to the competition, the existing World (WR) and Championship (CR) records were as follows.

* WR: 4:08.26 swum by Michael Phelps (USA) on 14 August 2004 in Athens, Greece.
* CR: 4:09.09 swum by Michael Phelps (USA) on 27 July 2003 in Barcelona, Spain

## Results

### Final

| Place | Swimmer | Nation | Time |
| - | - | - | - |
| 1 | László Cseh | Hungary | 4:09.63 |
| 2 | Luca Marin | Italy | 4:11.67 |
| 3 | Oussama Mellouli | Tunisia | 4:13.47 |
| 4 | Alessio Boggiatto | Italy | 4:13.48 |
| 5 | Ryan Lochte | USA | 4:13.67 |
| 6 | Hidemasa Sano | Japan | 4:17.72 |
| 7 | Robert Margalis | USA | 4:17.93 |
| 8 | Ioannis Drymonakos | Greece | 4:19.12 |

### Preliminaries

| Rank | Heat+Lane | Swimmer | Nation | Time | Notes |
| - | - | - | - | - | - |
| 1 | H5 L4 | László Cseh | Hungary | 4:14.15 | q |
| 2 | H5 L5 | Luca Marin | Italy | 4:15.18 | q |
| 3 | H5 L6 | Robert Margalis | United States | 4:16.25 | q |
| 4 | H4 L4 | Alessio Boggiatto | Italy | 4:16.46 | q |
| 5 | H4 L5 | Ioannis Drymonakos | Greece | 4:16.84 | q |
| 6 | H3 L4 | Oussama Mellouli | Tunisia | 4:17.21 | q |
| 7 | H3 L3 | Ryan Lochte | United States | 4:17.26 | q |
| 8 | H5 L3 | Hidemasa Sano | Japan | 4:17.64 | q |
| 9 | H3 L6 | Nicolas Rostoucher | France | 4:20.00 | |
| 10 | H4 L2 | Taishi Okude | Japan | 4:20.71 | |
| 11 | H5 L7 | Robin van Aggele | Netherlands | 4:20.90 | |
| 12 | H4 L6 | Igor Berezutsky | Russia | 4:20.98 | |
| 13 | H3 L2 | Dean Kent | New Zealand | 4:21.04 | |
| 14 | H4 L3 | Travis Nederpelt | Australia | 4:21.10 | |
| 15 | H3 L5 | Ioannis Kokkodis | Greece | 4:23.82 | |
| 16 | H3 L7 | Dmytro Nazarenko | Ukraine | 4:24.15 | |
| 17 | H5 L2 | Adam Lucas | Australia | 4:24.24 | |
| 18 | H2 L1 | Mihail Alexandrov | Bulgaria | 4:25.50 | |
| 19 | H3 L1 | Bradley Ally | Barbados | 4:28.91 | |
| 20 | H3 L8 | Paulius Andrijauskas | Lithuania | 4:29.25 | |
| 21 | H2 L2 | Miguel Molina | Philippines | 4:30.95 | |
| 22 | H4 L1 | Sebastian Stoss | Austria | 4:31.25 | |
| 23 | H2 L5 | Hocine Haciane | Andorra | 4:31.33 | |
| 24 | H2 L8 | Shaune Fraser | Cayman Islands | 4:31.90 | |
| 25 | H1 L4 | Dmitriy Gordiyenko | Kazakhstan | 4:32.05 | |
| 26 | H2 L4 | Guntars Deicmans | Latvia | 4:34.00 | |
| 27 | H2 L3 | Yury Zaharov | Kyrgyzstan | 4:39.22 | |
| 28 | H1 L5 | Vasilii Danilov | Kyrgyzstan | 4:40.07 | |
| 29 | H5 L8 | Sheng-hieh Tang | Chinese Taipei | 4:41.75 | |
| 30 | H4 L8 | Yu-An Lin | Chinese Taipei | 4:44.06 | |
| 31 | H2 L7 | Lionel Lee | Singapore | 4:46.60 | |
| 32 | H1 L3 | Francisco Montenegro | Guatemala | 4:49.14 | |
| 33 | H1 L6 | Johnny Castillo | Panama | 4:52.21 | |
| - | - | Mohamad Al-Naser | Kuwait | DNS | |
| - | - | Keith Beavers | Canada | DNS | |
| - | - | Sébastien Rouault | France | DNS | |
