Kim Clijsters of Belgium returns the ball to Julia Vakulenko of Ukraine during their second round match of the J and S Cup tennis tournament in Warsaw May 3, 2007. [Photo: Peter Andrews/Reuters]

Former world number one Kim Clijsters announced on Sunday that she has made up her mind to retire from tennis.

She said on her web diary that "it has been more than great.  The rackets will be hung up."

Clijsters, 23, has struggled with injury over the last few years and had said this season would be her last. The Belgian former U.S. Open champion, who is getting married in July, had already pulled out of the French and U.S. Opens.

"It would be easy to go on for a few more months and go to the four big earners in tennis," Clijsters wrote.

"Money is important but not the most important thing in my life. Health and private life are more important.

Clijsters said last week she did not want to risk getting injured again and having to wear a cast at her wedding to American basketball player Brian Lynch.

But she added then she planned to play at Eastbourne and Wimbledon in June.

Sunday's announcement means the Belgian played her last tournament in Warsaw last week, where she was defending the Warsaw Cup but looked short of form and lost in the second round to Ukrainian qualifier Julia Vakulenko.