"I think I will stop at the end of 2007. My body is already giving me a lot of problems," the 22-year-old Belgian said.
Clijsters has suffered from a series of injuries since 2003 when she became the first women's player since 1974 to play more than 100 singles matches in a season.
She returned from a career-threatening left wrist injury in February and has also suffered a knee injury this year. Despite these setbacks she has won six titles in 2005 including in Toronto last weekend.
Clijsters is seeded fourth at the final grand slam tournament of the year, the U.S. Open, which starts on Monday.
"I like to win and I put in a lot to do that but the quality of life in and outside tennis are at least as important," she said. Clijsters broke up with her long-time Australian boyfriend Lleyton Hewitt in October.
Strong and solidly built, Clijsters won nine singles titles and seven doubles finals in 2003, becoming the first Belgian to reach number one in August despite never winning one of the four grand slam tournaments.
In early 2004 she lost her fourth grand slam final at the Australian Open where she was troubled by an ankle injury. In June she had an operation on her wrist and missed the rest of the 2004 season.
After thrashing her compatriot and great rival Justine Henin-Hardenne in the Toronto final last weekend, Clijsters said her Achilles tendon was giving her problems.
"It might sound odd but it's all becoming tougher on me - the tournaments, the travelling. I can't see myself playing for more than two or three years," she said on her Web site.