O'Donnell, now the Republican Senate nominee in Delaware, has described herself as a devout Catholic and she targeted evangelical voters during her successful primary campaign.
Maher opened this season of his show with an O'Donnell clip from 1999 that features her saying, "I dabbled into witchcraft" and describing a date that included a "satanic altar" and blood.
Last week Maher showed a 1998 clip featuring O'Donnell saying she did not believe in evolution. "Evolution is a myth," O'Donnell said. If not, "Well then why aren't monkeys still evolving into humans?"
Maher had promised to show a clip each week until O'Donnell comes onto his show. He said he has 22 episodes that he's order. In tonight's opener Maher said he feels bad for showing clips that have been damaging to O'Donnell's candidacy but "then the feeling passes" when he thinks about what kind of senator she would be.
Our coverage of this race is here.
Watch tonight's clip: