Katsav was convicted at a court in Tel Aviv and was visibly shaken while the judge was reading out the guilty verdicts.
With live reports on Israeli television, this unprecedented criminal conviction of a top public official marked the climax of a four-and-a-half year saga that gripped the nation.
Claims that Katsav had raped and sexually assaulted his young, female staffers first surfaced when he was still president.
In 2006, he complained that a female employee was trying to blackmail him. The woman then went to police with allegations of sexual assault, prompting others to come forward with similar complaints.
Moshe Katsav resigned from the largely ceremonial post of head of state in 2007 and was indicted in March 2009.
He was found guilty of raping an employee in the 1990s when he was tourism minister and of later sexual offences while he was president.
The judges said they believed the evidence of the woman whose testimony had led to two charges of rape.
While his resignation caused shock across Israel, it had limited political consequences.
Rape commands a jail term in Israel of at least four years, although Katsav is thought to be likely to contest the conviction in Israel’s Supreme Court.
State prosecutor Ronit Amiel said the verdict carried a message to other victims of abuse of power that they should not remain silent.
Content lifted from BBC