The women shared the allegations during a press conference on Wednesday that began at 11 a.m. in California.
Coleen Hughes, one of the three victims, recalled she met Cosby while she worked as a stewardess on a flight heading to L.A. in the 70s, reports CBS LA.
Cosby has been accused by more than 30 women of sexual misconduct. The scandal forced Cosby to resign from the board of trustees at Temple University, and led NBC and Netflix to pull the plug on a comedy series he was working on. Reruns of "The Cosby Show" have also been pulled and his statue removed from the Walt Disney World theme park.
Hughes explained that when they landed, Cosby offered to take her to a nice lunch in Beverly Hills at the Miramar Hotel, now known as the Fairmont Hotel. After they arrived at the hotel, Hughes took a shower in Cosby's hotel room while he watched television. She said she exited the bathroom fully dressed, and she shared a glass of champagne with the comedian.
Hughes said hours later she woke up in a confused state. She realized then that she had been sexually assaulted.
CBS LA reports that Allred said the two other victims acted in feature films or television and theater.
One of the other victims, who identified herself as Linda, accused Cosby of sexually assaulting her while she sat in a chair awaiting a job interview. But Linda said she was not drugged during the assault.
Bill Cosby admitted in 2005 that he got quaaludes with the intent of giving them to young women he wanted to have sex with, and that he gave the sedative to at least one woman and "other people," according to a deposition that was recently unsealed.
CBS LA reports that Cosby has been ordered to give a sworn deposition in court on Oct. 9 in a lawsuit filed by Judith Hill, one of the many women who claims she was sexually assaulted by the comedian.
Cosby, 78, and his attorneys deny any wrongdoing.