Cosby admitted that in 1976 he had supplied Quaaludes - a strong depressant widely used in the 1960s and 70s, but which has been discontinued in the United States - to a woman who later accused him of sexual assault.
The disgraced television icon, who is accused of sex abuse by some 30 women spanning four decades, made the admission in a deposition in 2005.
The 77-year-old actor was questioned by Dolores Troiani, a lawyer for Andrea Constand, a former women's basketball director at Philadelphia's Temple University where Cosby studied and was, until recently, a member of the board of trustees.
Cosby's lawyers had long sought to block publication of the court transcripts, but they were released yesterday on the PACER public court records website.
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The comedian's attorneys had argued that his right to privacy meant the records should be kept sealed.
US District Court Judge Eduardo Robreno rejected that argument in a memo yesterday, highlighting "the stark contrast between Bill Cosby, the public moralist and Bill Cosby, the subject of serious allegations concerning improper (and perhaps criminal) conduct."
Robreno added that the public has "a significant interest" in the deposition.
The family sitcom was a huge hit in the 1980s and 1990s, making the actor a household name in the US and around the world.
Before fronting The Cosby Show, Cosby was already famous as a standup comedian and as one of the few black actors at the time to land lead roles, including in the hit secret-agent TV series "I Spy."
But from one of America's best-loved celebrities Cosby has gone to one of its most reviled.
He has also canceled several planned comedy engagements and a Cosby television special that was planned for late last year was scuttled.