The nine singers from various different seasons have joined together to sue the Fox competition for allegedly forcing them out of the show, reports TMZ.
The current Idol panel
The ex-contestants claim that they were axed as part of a racist plot to boost ratings for the network.
A letter has been submitted to the US Equal Employment Opportunity Commission by New York attorney James H Freeman, stating that he wants permission to sue Idol and Fox on behalf of his nine clients.
The acts in question are: Corey Clark (Season 2), Jaered Andrews (Season 2), Donnie Williams (Season 3), Terrell Brittenum (Season 5), Derrell Brittenum (Season 5), Thomas Daniels (Season 6), Akron Watson (Season 6), Ju'Not Joyner (Season 8) and Chris Golightly (Season 9).
Freeman claims that he conducted an investigation into the show after Jermaine Jones was booted off last year in relation to outstanding warrants for his arrest.
[Left: Corey Clark - Season 2 / Right: Derrell and Terrell Brittenum - Season 5]
He says that he discovered producers had only publicly disqualified nine people from the programme, and they were all black.
The letter states that Freeman believes the Idol "scheme" starts at a background stage of the show, when producers are said to ask contestants: "Have you ever been arrested?"
He claims that the question is a violation of California employment law, and because the contestants are technically applying for "employment" with Idol, the show was not allowed to ask about their arrest history.
Freeman adds that the question coupled with arrest records acquired by private investigators were used to humiliate the black Idol contestants on national TV, and to create "destructive stereotypes" about black people.
He also states that the show made his clients seem to be "violent criminals, liars and sexual deviants", adding that the show "never once publicly disqualified a white or non-black American Idol contestant in the history of the 11-season production".
Freeman also alleges that none of the nine contestants were ever convicted of their crimes for which they were charged at the time.
He writes: "Yet their personal and professional lives remain permanently and severely impaired by [the show's] continuing violations of our nation's laws."
American Idol executive producer Nigel Lythgoe said that he was "shocked" by the "ridiculous" allegations.
He said: "We treat everybody the same... no matter the race, religion or sex.
"I think we've always had a fantastic share of talent from contestants both black and white... I don't think I've ever seen racism at the show."
American Idol returned for its 12th season on Fox last week, with a returning judging panel consisting of Mariah Carey, Nicki Minaj, Keith Urban and Randy Jackson.