He said: "I never took bribes, I never took a penny for myself. I was elected by you to be prime minister of Israel and I am not shying away from that responsibility."
Olmert confirmed he would not fight to stay in office if he is charged.
"If I am indicted, I will resign my post," he said.
Olmert's statement came after police lifted a media gag order that had prevented the Israeli media from reporting on the investigation, and announced details of the accusations.
The investigation has increased pressure on Olmert to quit, and doubt over his future is likely to disrupt faltering peace negotiations with the Palestinians.