The 60 year old was admitted to the Hadassah hospital after apparently being taken ill but was discharged two hours later as, according to armed forces radio, his condition did not justify a hospital stay.
"The president's condition is fine," said Mr Katsav's spokesman Hagit Cohen. He refused to comment on reports Katsav had undergone hospital tests.
The hospital declined to provide any details.
After a three-month investigation, Israeli police recommended charges should be brought against the president for rape and sexual harassment.
But Mr Katzav has claimed to be the victim of a smear campaign and has refused to step down provisionally as the attorney general has requested.
Under the law he cannot face prosecution until he resigns or is stripped of his post to avoid damaging the presidential office.
The Israeli president is elected for seven years and Katzav's term ends in July 2007.