Concert promoter Ticketmaster is offering refunds for Bill Cosby'sshows this weekend in Denver.
More than 3,000 tickets have been sold to Saturday's performances, according to local media.
Organisers say they have a "moral obligation" for the shows to go on, amid planned protests.
Cosby has been accused by more than 15 women of sexual assaults dating back to the 1970s and '80s, leading to the cancellation of several planned shows.
The 77-year-old, who has not been charged, has denied claims, calling them "fantastical" and "uncorroborated".
Another of his shows - a 6 February date at the Hanover Theatre in Worcester, Massachusetts - has been cancelled after the promoters "came to an agreement" with his agent.
More than 1,000 tickets were sold for the performance at the venue, which seats an audience of 2,300.
Organisers AEG Live said it understood concerns some people had about the shows taking place, but said the company had a "moral obligation" to allow the comedian to perform.
"If the allegations turn out to be true, I'm going to be appalled and disgusted," AEG President Chuck Morris told Denver station KUSA-TV.
"But at this point, I feel like I have an obligation to the people that want to see the show and an artist that has not been charged or convicted."
Meanwhile, protests are being planned outside the Buell Theatre venue on Saturday during both performances.
Gloria Allred, a lawyer representing several women who have accused the comedian of either rape or sexual assault, is expected to speak and join the demonstration.
At least 10 dates on Cosby's North American stand-up tour, as well as some scheduled TV appearances, were cancelled following the initial allegations which surfaced last autumn.
The comedian's shows in Canada earlier this month went ahead, despite demonstrations outside the venue in Ontario.
More than a dozen protestors carried placards stating "rape is no joke" and some barred the entrance to the venue, before being asked to move by security.
Cosby became the quintessential American Dad in his role as Dr Cliff Huxtable on The Cosby Show from 1984 to 1992, a huge hit in the US and around the globe.