La competició de natació al Campionat del Món de natació de 2003 es realitzà a la piscina provisional construïda al Palau Sant Jordi (Barcelona).
Resum de medalles Categoria masculina 50 m, lliures Aleksandr Popov 21,92 (RC) Mark Foster 22,20 Pieter van den Hoogenband 22,29 100 m, lliures Aleksandr Popov 48,42 Pieter van den Hoogenband 48,68 Ian Thorpe 48,77 200 m, lliures Ian Thorpe 1:45,14 Pieter van den Hoogenband 1:46,43 Grant Hackett 1:46,85 400 m, lliures Ian Thorpe 3:42,58 Grant Hackett 3:45,17 Dragoş Coman 3:46,87 800 m, lliures Grant Hackett 7:43,82 Larsen Jensen 7:48,09 Igor Chervynskyi 7:53,15 1500 m,lliures Grant Hackett 14:43,14 Igor Chervynskyi 15:01,04 Erik Vendt 15:01,28 50 m, esquena Thomas Rupprath 24,80 (RM) Matt Welsh 25,01 Gerhard Zandberg 25,07100 m, esquena Aaron Peirsol 53,61 (RC) Arkady Vyatchanin Matt Welsh 53,92 no es concedí 200 m, esquena Aaron Peirsol 1:55,92 Gordan Kožulj 1:57,47 Simon Dufour 1:57,90 50 m, braça James Gibson 27,56 Oleg Lisogor 27,74 Mihaly Flaskay 27,79 100 m, braça Kosuke Kitajima 59,78 (RM) Brendan Hansen 1:00,21 James Gibson 1:00,37 200 m, braça Kosuke Kitajima 2:09,42 (RM Ian Edmond 2:10,92 Brendan Hansen 2:11,11 50 m, papallona Matt Welsh 23,43 (RM) Ian Crocker 23,62 Yevgeny Korotyshkin 23,73 100 m, papallona Ian Crocker 50,98 (RM) Michael Phelps 51,10 Andrei Serdinov 51,59 200 m, papallona Michael Phelps 1:54,35 Takashi Yamamoto 1:55,52 Tom Malchow 1:55,66 200 m, estils Michael Phelps 1:56,04 (RM) Ian Thorpe 1:59,66 Massimiliano Rosolino 1:59,71 400 m, estils Michael Phelps 4:09,09 (RM) László Cseh 4:10,79 Oussama Mellouli 4:15,36 relleus 4×100 m, lliures Andrei Kapralov Ivan Usov Denis Pimankov Aleksandr Popov 3:14,06 Scott Tucker Neil Walker Ryan Wochomurka Jason Lezak 3:14,80 Romain Barnier Julien Sicot Fabien Gilot Frédérick Bousquet 3:15,66 relleus 4×200 m, lliures Grant Hackett Craig Stevens Nicholas Sprenger Ian Thorpe 7:08,58 Michael Phelps Nate Dusing Aaron Peirsol Klete Keller 7:10,26 Johannes Oesterling Lars Conrad Stefan Herbst Christian Keller 7:14,02 relleus 4×100 m, estils Aaron Peirsol Brendan Hansen Ian Crocker Jason Lezak 3:31,54 (RM) Arkady Vyatchanin Roman Ivanovski Igor Marchenko Aleksandr Popov 3:34,72 Tomami Morita Kosuke Kitajima Takashi Yamamoto Daisuke Hosokawa 3:36,12 Llegenda:
Categoria femenina 50 m, lliures Inge de Bruijn 24,47 Alice Mills 25,07 Libby Lenton 25,08 100 m, lliures Hanna-Maria Seppälä 54,37 Jodie Henry 54,58 Jenny Thompson 54,65 200 m, lliures Alena Popchanka 1:58,32 Martina Moravcová 1:58,44 Yu Yang 1:58,54 400 m, lliures Hannah Stockbauer 4:06,75 Éva Risztov 4:07,24 Diana Munz 4:07,67 800 m, lliures Hannah Stockbauer 8:23,66 (RC) Diana Munz 8:24,19 Rebecca Cooke 8:28,45 1500 m, lliures Hannah Stockbauer 16:00,18 (RC) Hayley Peirsol 16:09,64 Jana Henke 16:10,13 50 m, esquena Nina Zhivanevskaya 28,48 (RC) Ilona Hlaváčková 28,50 Noriko Inada 28,62 100 m, esquena Antje Buschschulte 1:00,50 Louise Ørnstedt Katy Sexton 1:00,86 No es concedí 200 m, esquena Katy Sexton 2:08,74 Margaret Hoelzer 2:09,24 Stanislava Komarova 2:10,17 50 m, braça Xuejuan Luo 30,67 Brooke Hanson 31,13 Zoë Baker 31,37 100 m, braça Xuejuan Luo 1:06,80 Amanda Beard 1:07,42 Leisel Jones 1:07,47 200 m, braça Amanda Beard 2:22,99 (RM) Leisel Jones 2:24,33 Hui Qi 2:25,78 50 m, papallona Inge de Bruijn 25,84 RC) Jenny Thompson 26,00 Anna-Karin Kammerling 26,06 100 m, papallona Jenny Thompson 57,96 (RC) Otylia Jędrzejczak 58,22 Martina Moravcová 58,24 200 m, papallona Otylia Jędrzejczak 2:07,56 Éva Risztov 2:07,68 Yuko Nakanishi 2:08,08 200 m, estils Yana Klochkova 2:10,75 Alice Mills 2:12,75 Yafei Zhou 2:12,92 400 m, estils Yana Klochkova 4:36,74 Éva Risztov 4:37,39 Beatrice Căslaru 4:41,86relleus 4x100 m, lliures Natalie Coughlin Lindsay Benko Rhi Jeffrey Jenny Thompson 3:38,09 Petra Dallmann Katrin Meißner Antje Buschschulte Sandra Völker 3:38,73 Lisbeth Lenton Elka Graham Jodie Henry Alice Mills 3:38,83relleus 4x200 m, lliures Lindsay Benko Rachel Komisarz Rhi Jeffrey Diana Munz 7:55,70 (RC) Elka Graham Linda Mackenzie Kirsten Thompson Alice Mills 7:58,42 Yafei Zhou Yanwei Xu Jiaying Pang Yu Yang 7:58,53relleus 4x100 m, estils Shu Zhan Xuejuan Luo Yafei Zhou Yu Yang 3:59,89 (RC) Natalie Coughlin Amanda Beard Jenny Thompson Lindsay Benko 4:00,83 Giaan Rooney Leisel Jones Jessicah Schipper Jodie Henry 4:01,37 Llegenda:
Medaller 1 11 12 5 28 2 6 10 6 22 3 5 1 2 8 4 3 2 2 7 5 3 0 4 7 6 2 3 3 8 7 2 2 2 6 8 2 2 1 5 9 2 1 3 6 10 1 1 0 2 11 1 0 0 1 1 0 0 1 1 0 0 1 14 0 4 1 5 15 0 1 1 2 16 0 1 0 1 0 1 0 1 0 1 0 1 19 0 0 2 2 0 0 2 2 21 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 Total 40 42 38 120
Categoria:Campionat del Món de natació de 2003