Luo Xuejuan, China's only swimming gold medalist three years ago in the Athens Olympics, is retiring with what Chinese officials called heart problems.
Luo's retirement was reported across China on Tuesday.
Luo, 23, won gold in the 100-metre breaststroke in Athens, but last month was left off China's team at the Asian Games in Doha, Qatar.
Luo's future has been in question and shrouded in secrecy for months, with reports of her poor health and lack of training.
"It has been seven years since I joined the national team, which I always regard as my home," she told reporters.
"As an Olympic and world champion, I will try to make contributions for the Beijing Olympic Games."
Without giving details of Luo's heart problem, Chinese swim officials said the ailment would not allow her to compete, but would not affect her daily life.
China's swimming programme has often been filled with surprises and disappointments.
It was also involved in an embarrassing series of doping scandals in the 1990s, with 32 Chinese swimmers caught for drug offences.
{{/usCountry}}It was also involved in an embarrassing series of doping scandals in the 1990s, with 32 Chinese swimmers caught for drug offences.
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