Katsav arrived at the Supreme Court in Jerusalem this morning, accompanied by his lawyers, to appeal his conviction and sentence, a justice ministry official said on condition of anonymity.
Katsav will appear before judges Edna Arbel, Myriam Nahor and Selim Jubran to appeal his December conviction on charges of rape, sexual harassment, indecent acts and obstruction of justice.
He will also challenge a seven-year prison sentence, handed down in March along with a two-year suspended sentence and an order he pay compensation of 100,000 shekels ($28,000/20,000 euros) to the main victim, known only as "Aleph", as well as 25,000 shekels ($7,000/5,000 euros) to a second victim.
Throughout the 18-month trial, which included harrowing accusations, the former president was portrayed as a sexual predator who routinely harassed his female staff.
But he has denied the charges against him, saying he was the target of a media plot and that his interactions with his female staff were consensual.
The former president was scheduled to report to prison to begin serving his sentence on May 8, but Supreme Court justice Yoram Danziger agreed to delay the beginning of Katsav's sentence until he completed his appeal.