The 20-year-old said she will instead stay loyal to her own clothing sponsor rather than wear a rival company's official Belgian uniform at the Games.
Clijsters said on Monday she wanted to "remain fair" to her sponsors -- Italian clothing manufacturer Fila -- after they had shown faith in her two years ago. She has repeatedly said she will not wear tennis clothing from Belgium's Olympic sponsor Adidas.
"As long as my clothing remains an issue, it is impossible for me to go to the Olympics," Clijsters said last month.
On Monday she said she had reached a decision.
"I've decided not to go to the Olympic Games," she said in a diary for her official website.
"I want to remain fair to the people I made a contract with. They were the only ones who wanted me two years ago."
The International Olympic Committee's Belgian president, Jacques Rogge said he would not intervene in the matter.
"It is a question of solidarity that all athletes participating in the Olympic Games wear the same uniform. I feel sad to hear that Clijsters will not be in Athens, but she is still young and I am sure that as time passes, she will reflect on that decision," Rogge told television channel VTM.
"She will realise she missed a real opportunity to win a medal, but I respect her decision.
"No, I will not try to make her change her mind, that is not my role. The Belgian Olympic Committee and Kim are big enough to solve the matter between them."
GOOD-LUCK WISH
Clijsters wished her compatriot Justine Henin-Hardenne -- already sponsored by Adidas -- luck at the Olympics.
"I really hope Justine takes the gold in Athens and hopefully the other Belgians take plenty of medals as well," she said. "I'll be their number one supporter."
However, Clijsters will fly the flag for her Fed Cup team next year after turning her back on the Belgian cause last month.
Missing Clijsters and her number one-ranked compatriot Henin-Hardenne, the Belgian team -- including Clijsters' younger sister Elke -- fell in the semi-finals to an under-strength U.S. team.
Clijsters had made no secret of her disappointment when Moscow was made host for the Fed Cup semi-final and final before withdrawing from the Belgian squad.
Speaking from Australia where she watched boyfriend Lleyton Hewitt help capture the Davis Cup title for Australia, Clijsters said: "The atmosphere was comparable with the Fed Cup in my home town Bree. Next year I'll play the Fed Cup again because the event will probably be organised in Bree again.
"I also want Belgium to stay in the world group and the event fits in my schedule."
