De Klerk, 70, walked out of Cape Town's Panorama Medi-Clinic supported by a cane, telling journalists he would rest for a while before resuming his philanthropic work on Aug. 15, the South African Press Association reported.
He suffered a serious lung infection after having a colon tumor removed June 3.
"Mr. De Klerk's doctors did not find any additional cancerous sites during and after his initial operation," his foundation said. "His prognosis remains excellent. However, he will be consulting with them during the coming weeks on the advisability of taking a preventative course of chemotherapy."
De Klerk thanked doctors, hospital staff and the thousands around the world who expressed support and concern during his illness.
"I've been surrounded by love," he said outside the hospital.
De Klerk took over as president from hard-line white nationalist P.W. Botha in 1989. Six months later, he stunned the world by freeing anti-apartheid icon Nelson Mandela after 27 years in prison and beginning negotiations that culminated in South Africa's first all-race elections in 1994.
De Klerk's efforts won him a share of the Nobel Peace Prize with Mandela in 1993, but also cost his National Party its place at the pinnacle of power. He served as a deputy president in Mandela's power-sharing government, but quit in 1996 and resigned as party leader a year later.
Since quitting politics in 2004, he has set up foundations in London and Cape Town to promote peace, democracy and understanding.