The men's 400 metres at the 2009 World Championships in Athletics was held at the Olympic Stadium on 18, 19 and 21 August. The winning margin was 0.54 seconds.

The United States had a strong tradition in the event, with an American topping the Olympic 400 m podium every time since the 1988 Olympics. Similar to the 2007 World Championships, Jeremy Wariner and LaShawn Merritt were the clear favourites. However, on this occasion, recent form favoured the Olympic champion Merritt instead of the reigning world champion Wariner. Both Americans were undefeated that season but Merritt held the world-leading time of 44.50 seconds. A gold or silver medallist outside of these two competitors seemed unlikely; Bahamian Chris Brown, Irishman David Gillick, Frenchman Leslie Djhone and the other two runners from the United States (Gil Roberts and Lionel Larry) were seen to be capable of a bronze at best.Ramsak, Bob (2009-08-09). Men's 400m - PREVIEW . IAAF. Retrieved on 2009-08-18.

On the first day, Ramon Miller surprised as the fastest qualifier in the heats, scoring a new personal best of 45 seconds. Tabarie Henry, Djhone and Renny Quow were the next fastest, and African record holder Gary Kikaya was most high-profile casualty of the first round, having been disqualified for a lane infraction.Ramsak, Bob (2009-08-09). Event Report - Men's 400m - Heats . IAAF. Retrieved on 2009-08-18.

Medalists GoldSilverBronzeLaShawn MerrittJeremy WarinerRenny Quow

Records Prior to the competition, the established records were as follows. World record43.18Seville, Spain26 August 1999Championship record43.18Seville, Spain26 August 1999World Leading44.50Baie-Mahault, France3 July 2009African record44.10Stuttgart, Germany9 September 2006Asian record44.56Budapest, Hungary12 August 1988North American record43.18Seville, Spain26 August 1999South American record44.29Seville, Spain26 August 1999European record44.33Rome, Italy3 September 1987Oceanian record44.38Seoul, South Korea26 September 1988

Qualification standards A timeB time 45.55 45.95

Schedule Date Time RoundAugust 18, 2009 11:05 HeatsAugust 19, 2009 18:15 SemifinalsAugust 21, 2009 21:20 Final

Results

Heats Qualification: First 3 in each heat(Q) and the next 3 fastest(q) advance to the semifinals.

Rank Heat Name Nationality Time Notes 5 Ramon Miller 45.00 Q, PB 7 Tabarie Henry 45.14 Q 5 Leslie Djhone 45.20 Q 2 Renny Quow 45.21 Q 4 LaShawn Merritt 45.23 Q 7 Sean Wroe 45.31 Q 4 John Steffensen 45.37 Q 7 Martyn Rooney 45.45 Q 1 Robert Tobin 45.50 Q 10 2 William Collazo 45.52 Q 11 3 Chris Brown 45.53 Q 12 6 Jeremy Wariner 45.54 Q 12 1 David Gillick 45.54 Q 12 3 Michael Bingham 45.54 Q 15 1 Rabah Yousif 45.55 Q, PB 15 7 Erison Hurtault 45.55 q, SB 17 3 Joel Milburn 45.56 Q, SB 17 7 Mohamed Ashour Khouaja 45.56 q, NR 19 6 Ricardo Chambers 45.57 Q 20 2 Kevin Borlée 45.61 Q 21 1 Lionel Larry 45.64 q 22 2 Marcin Marciniszyn 45.77 SB 23 5 Johan Wissman 45.83 Q 24 4 Matteo Galvan 45.86 Q, PB 25 5 Maksim Dyldin 45.91 26 1 Young Talkmore Nyongani 45.92 27 1 Cédric Van Branteghem 45.94 28 4 Héctor Carrasquillo 46.11 29 2 Arismendy Peguero 46.13 30 6 Teddy Venel 46.16 Q 31 3 Eric Milazar 46.39 32 5 Gil Roberts 46.41 33 7 Saul Weigopwa 46.42 34 3 Isaac Makwala 46.45 35 4 Alvin Harrison 46.67 36 3 Nagmeldin Ali Abubakr 46.48 37 1 Hideyuki Hirose 46.80 38 6 Yuzo Kanemaru 46.83 39 7 Rondell Bartholomew 46.85 40 3 Andrés Silva 46.86 41 2 Mathieu Gnanligo 47.00 SB 42 6 Yousef Ahmed Masrahi 47.03 43 5 Mark Kiprotich Muttai 47.04 44 2 Nelson Stone 47.13 45 6 Pieter Smith 48.14 46 5 Naiel d'Almeida 49.47 47 7 Moumouni Kimba 50.93 PB 48 3 Zaw Win Thet 51.41 PB 2 Michael Mathieu 4 Gary Kikaya 4 Yannick Fonsat 5 James Godday 6 Nery Brenes

Key: NR = National record, PB = Personal best, Q = qualification by place in heat, q = qualification by overall place, SB = Seasonal best

Semifinals First 2 in each semifinal(Q) and the next 2 fastest(q) advance to the final. Rank Heat Name Nationality Time Notes 2 LaShawn Merritt 44.37 Q, WL 2 Renny Quow 44.53 Q, PB 1 Jeremy Wariner 44.69 Q 1 Michael Bingham 44.74 Q, PB 1 Leslie Djhone 44.80 q, SB 1 David Gillick 44.88 q 2 William Collazo 44.93 3 Chris Brown 44.95 Q 3 Tabarie Henry 44.97Q 10 1 Ramon Miller 44.99 PB 11 3 Ricardo Chambers 45.13 SB 12 3 Kevin Borlée 45.28 SB 13 2 Sean Wroe 45.32 14 3 John Steffensen 45.50 15 2 Erison Hurtault 45.59 16 2 Rabah Yousif 45.63 17 3 Lionel Larry 45.85 18 3 Robert Tobin 45.90 19 2 Martyn Rooney 45.98 20 1 Joel Milburn 46.06 21 2 Teddy Venel 46.30 22 1 Mohamed Ashour Khouaja 46.43 23 3 Matteo Galvan 46.87 1 Johan Wissman

Final Rank Name Nationality Time Notes LaShawn Merritt 44.06 WL Jeremy Wariner 44.60 SB Renny Quow 45.02 4 Tabarie Henry 45.42 5 Chris Brown 45.47 6 David Gillick 45.53 7 Michael Bingham 45.56 8 Leslie Djhone 45.90

References General 400 metres results. IAAF. Retrieved on 2009-08-18. Specific