The New York Post reported that the 68-year-old conservative talk show host made the announcement at 7:15 a.m. EDT.
Imus lost his CBS radio show and MSNBC simulcast in 2007 after he made racist and sexist comments about the Rutgers University women's basketball team. He issued a public apology to the team and the African-American community and was later hired by another network. He returned to the airwaves on ABC Radio Networks and cable's RFD-TV eight months after being fired.
Usmagazine.com quoted the shock jock as saying Monday that he was diagnosed with prostate cancer last Wednesday.
"The day you find out is fine," Imus said. "But the next morning when you get up, your knees are shaking. I didn't think I could make it to work. ... I don't want to have great arrogance about it but I have great doctors. I'll be fine. And if I'm not fine, it's no big deal. ... The prognosis couldn't be better."