Prosecutors also charged the 62-year-old father of five with indecent acts and of suborning a witness.
Katsav, who has effectively pleaded guilty, must now appear in court for his formal conviction and sentencing, for which no date has yet been set.
If the court rules that his crimes were "vile," Katsav could lose the comfortable pension, apartment, office, two secretaries and car and driver that he is entitled to as ex-president.
He would also receive a suspended sentence and a fine.
On Tuesday, a panel of five judges voted 3-2 to reject petitions to overturn last June's plea bargain, which led to Katsav resigning in disgrace.
Katsav will become Israel's first head of state convicted of sex offenses and the second to be forced out of the largely ceremonial office by scandal.
His predecessor, the late Ezer Weizman, was forced to resign in 2000 after revelations that he received around $450,000 from a French millionaire while a minister and a lawmaker.
The Katsav affair is just one of many scandals to afflict the Israeli leadership in recent years.
In November, police decided that there was insufficient evidence to indict Prime Minister Ehud Olmert in a graft case involving the privatization of a major bank when Olmert was acting finance minister in 2005.
And a son of former premier Ariel Sharon began a seven-month jail term Wednesday for campaign law financing irregularities in connection with his father's bid for the Likud party leadership.
Güncelleme Tarihi: 28 Şubat 2008, 18:05