# Swimming at the 2003 World Aquatics Championships – Men's 100 metre backstroke

The Men's 100 Backstroke event at the 10th FINA World Aquatics Championships swam 21 – 22 July 2003 in Barcelona, Spain. Preliminary and Semifinal heats swam on July 21; the Final was held on July 22.
At the start of the event, the existing World (WR) and Championship (CR) records were:
* WR: 53.60 swum by Lenny Krayzelburg (USA) on August 24, 1999 in Sydney, Australia
* CR: 54.31 swum by Matt Welsh (Australia) on July 23, 2001 in Fukuoka, Japan

## Results
### Final

| Place | Swimmer | Nation | Time | Notes |
| 1 | Aaron Peirsol | USA | 53.61 | CR |
| 2 | Arkady Vyatchanin | Russia | 53.92 | |
| 2 | Matt Welsh | Australia | 53.92 | |
| 4 | Steffen Driesen | Germany | 54.17 | |
| 5 | Markus Rogan | Austria | 54.53 | |
| 6 | Tomomi Morita | Japan | 54.86 | |
| 7 | László Cseh | Hungary | 54.95 | |
| 8 | Alex Lim | Malaysia | 55.18 | |

### Semifinals

| Rank | Heat + Lane | Swimmer | Nation | Time | Notes |
| 1 | S2 L5 | Aaron Peirsol | USA | 54.28 | q, CR |
| 2 | S1 L4 | Arkady Vyatchanin | Russia | 54.49 | q |
| 3 | S1 L1 | Steffen Driesen | Germany | 54.60 | q |
| 4 | S2 L4 | Matt Welsh | Australia | 54.77 | q |
| 4 | S2 L8 | Alex Lim | Malaysia | 54.77 | q |
| 6 | S2 L2 | Markus Rogan | Austria | 55.11 | q |
| 7 | S2 L3 | László Cseh | Hungary | 55.12 | q |
| 8 | S1 L5 | Tomomi Morita | Japan | 55.17 | q |
| 9 | S2 L6 | Ouyang Kunpeng | China | 55.21 | |
| 10 | S1 L3 | Blaž Medvešek | Slovenia | 55.30 | |
| 11 | S1 L7 | Simon Dufour | France | 55.31 | |
| 12 | S1 L8 | Atsushi Nishikori | Japan | 55.36 | |
| 13 | S2 L1 | Răzvan Florea | Romania | 55.42 | |
| 14 | S1 L2 | Örn Arnarson | Iceland | 55.67 | |
| 15 | S1 L6 | Yoav Gath | Israel | 55.71 | |
| 16 | S2 L7 | Péter Horváth | Hungary | 55.83 | |

### Preliminaries

| Rank | Heat+Lane | Swimmer | Nation | Time | Notes |
| 1 | H12 L4 | Matt Welsh | Australia | 54.79 | q |
| 2 | H10 L2 | Arkady Vyatchanin | Russia | 54.81 | q |
| 3 | H11 L4 | Aaron Peirsol | United States | 54.99 | q |
| 4 | H12 L6 | Tomoni Morita | Japan | 55.06 | q |
| 5 | H11 L7 | László Cseh | Hungary | 55.11 | q |
| 6 | H10 L8 | Blaž Medvešek | Slovenia | 55.28 | q |
| 7 | H11 L1 | Ouyang Kunpeng | China | 55.29 | q |
| 8 | H08 L4 | Yoav Gath | Israel | 55.41 | q |
| 9 | H11 L5 | Markus Rogan | Austria | 55.42 | q |
| 10 | H09 L8 | Örn Arnarson | Iceland | 55.47 | q |
| 10 | H10 L3 | Péter Horváth | Hungary | 55.47 | q |
| 12 | H11 L2 | Simon Dufour | France | 55.49 | q |
| 13 | H09 L1 | Răzvan Florea | Romania | 55.56 | q |
| 13 | H10 L5 | Steffen Driesen | Germany | 55.56 | q |
| 15 | H11 L6 | Alex Lim | Malaysia | 55.62 | q |
| 16 | H12 L5 | Atsushi Nishikori | Japan | 55.67 | q |
| 17 | H10 L7 | Riley Janes | Canada | 55.76 | |
| 18 | H12 L8 | Gerhard Zandberg | South Africa | 55.80 | |
| 19 | H12 L3 | Josh Watson | Australia | 55.81 | |
| 20 | H09 L5 | Karel Novy | Switzerland | 55.82 | |
| 21 | H12 L1 | David Ortega | Spain | 55.85 | |
| 22 | H12 L7 | Toni Helbig | Germany | 55.90 | |
| 23 | H10 L6 | Gordan Kožulj | Croatia | 55.94 | |
| 24 | H09 L4 | Ahmed Hussein | Egypt | 55.95 | |
| 25 | H08 L2 | Darius Grigalionis | Lithuania | 56.00 | |
| 26 | H08 L7 | Ryan Pini | Papua New Guinea | 56.06 | |
| 27 | H10 L1 | Volodymyr Nikolaychuk | Ukraine | 56.14 | |
| 28 | H09 L7 | Cameron Gibson | New Zealand | 56.22 | |
| 29 | H12 L2 | Evgueni Alechine | Russia | 56.31 | |
| 30 | H11 L3 | Pierre Roger | France | 56.34 | |
| 31 | H11 L8 | Min Sung | South Korea | 56.38 | |
| 32 | H07 L6 | Pavel Suškov | Lithuania | 56.42 | |
| 33 | H09 L2 | Jorge Sánchez | Spain | 56.44 | |
| 34 | H08 L6 | Klaas Erik Zwering | Netherlands | 56.58 | |
| 35 | H07 L4 | Pavlo Illichov | Ukraine | 56.60 | |
| 36 | H09 L3 | Rui Yu | China | 56.77 | |
| 37 | H09 L6 | Paulo Machado | Brazil | 57.01 | |
| 38 | H08 L3 | Nuno Laurentino | Portugal | 57.10 | |
| 39 | H08 L1 | Flori Lang | Switzerland | 57.12 | |
| 40 | H07 L7 | Jens Petersson | Sweden | 57.36 | |
| 41 | H07 L5 | Keith Beavers | Canada | 57.54 | |
| 42 | H07 L1 | Martin Viilep | Estonia | 57.69 | |
| 42 | H08 L5 | Sander Ganzevles | Netherlands | 57.69 | |
| 44 | H01 L6 | Mattias Ohlin | Sweden | 57.75 | |
| 45 | H08 L8 | Gabriel Mangabeira | Brazil | 58.08 | |
| 46 | H07 L3 | Alexandr Ivlev | Moldova | 58.53 | |
| 47 | H07 L2 | Andrei Mihailov | Moldova | 58.67 | |
| 48 | H07 L8 | Nicholas Bovell | Trinidad and Tobago | 59.42 | |
| 49 | H06 L4 | Mauricio Prudencio | Bolivia | 59.62 | |
| 50 | H06 L8 | Jared Heine | Marshall Islands | 1:00.13 | |
| 51 | H06 L3 | Ashby Brendan | Zimbabwe | 1:00.21 | |
| 52 | H06 L7 | Yau Sun Fai | Hong Kong | 1:00.87 | |
| 53 | H06 L2 | Guillermo Andres Ramirez Lemis | Colombia | 1:01.38 | |
| 54 | H06 L1 | Gustavo Vera | Paraguay | 1:01.44 | |
| 55 | H05 L4 | Long Do Huy | Vietnam | 1:02.06 | |
| 56 | H06 L5 | Mikhail Alekseyev | Uzbekistan | 1:02.38 | |
| 57 | H05 L1 | Roberto Sanso | Costa Rica | 1:02.40 | |
| 58 | H04 L3 | Khaly Ciss | Senegal | 1:02.49 | |
| 59 | H05 L5 | Danil Bugakov | Uzbekistan | 1:02.67 | |
| 60 | H05 L7 | Mohammad Nazeri | Iran | 1:02.75 | |
| 61 | H06 L6 | Yury Zaharov | Kyrgyzstan | 1:02.91 | |
| 62 | H04 L4 | James Walsh | Philippines | 1:03.72 | |
| 63 | H05 L3 | Abed Rahman Kaaki | Lebanon | 1:03.77 | |
| 64 | H05 L6 | Oleg Deikrishvili | Georgia | 1:03.84 | |
| 65 | H04 L5 | Chi Lon Lei | Macau | 1:03.86 | |
| 66 | H03 L5 | Onan Thom | Guyana | 1:03.91 | |
| 67 | H04 L6 | Ammar Musaed Al Tamimi | United Arab Emirates | 1:04.31 | |
| 68 | H04 L2 | Omar Abu Faris | Jordan | 1:04.45 | |
| 69 | H03 L6 | Seung Gin Lee | Northern Mariana Islands | 1:04.80 | |
| 70 | H05 L2 | Olufolahan Oluwole | Nigeria | 1:05.35 | |
| 71 | H04 L8 | Kabir Walia | Kenya | 1:05.50 | |
| 72 | H04 L1 | Rubel Mohammad Rubel Rana | Bangladesh | 1:05.62 | |
| 73 | H05 L8 | Rony Bakale | Republic of the Congo | 1:05.82 | |
| 74 | H03 L2 | Nuno Rola | Angola | 1:06.49 | |
| 75 | H02 L5 | Patrick Boustany | Lebanon | 1:07.14 | |
| 76 | H03 L3 | Daniel Kang | Guam | 1:07.92 | |
| 77 | H03 L4 | Urnultsaikhan Ganbold | Mongolia | 1:08.19 | |
| 78 | H03 L7 | Sean Chow | Fiji | 1:09.18 | |
| 79 | H02 L1 | Muzeya Muzyamba | Zambia | 1:10.71 | |
| 80 | H02 L6 | Kin-Vincent Duenas | Guam | 1:11.15 | |
| 81 | H01 L4 | Peter James Linch | Zambia | 1:12.30 | |
| 82 | H02 L2 | Leonel Matonse | Mozambique | 1:13.11 | |
| 83 | H02 L8 | Mohammed S. Abbas | Iraq | 1:13.75 | |
| 84 | H03 L8 | Hadjamamed Hadjamamedov | Turkmenistan | 1:14.23 | |
| - | - | Randall Bal | United States | DQ | |
| - | - | Landry H. Degnifo Enokorin | Ivory Coast | DNS | |
| - | - | Gibrilla Kanu | Sierra Leone | DNS | |
| - | - | Awsan Mohammede Saleh Qardaa | Yemen | DNS | |
| - | - | Hem Lumphar | Cambodia | DNS | |