Jamaica's Lorraine Fenton, one of the leading women's 400m runners in the last decade, announced her retirement on Wednesday.
Fenton won a 400m silver medal at the 2000 Olympic Games and also finished second over one lap at the the 2001 and 2003 World Championships.
She was also in the Jamaica team that won the 2001 world 4x400m relay.
"I celebrated my 33rd birthday last month and that was an appropriate time for reflection," said Fenton.
"I have had a very good career, some wonderful moments, but I'm a competitive person and realised that it was unlikely that I was going to be in contention again for an individual medal at the very highest levels."
Fenton, who set the Jamaican 400m record of 49.30 seconds in 2002, missed the entire 2004 season through injury but was in the Jamaican team that won silver at the 2005 world championships in Helsinki.
She added: "I have never quite been able to get back to the same level again even though I am proud of what I have been able to do in the last two years.
"If I could have stayed injury free I think I could again have got another Olympic medal in Athens. I know how much I wanted to get a gold medal after three successive silvers."