The 70-year-old Pulitzer Prize winner wrote in an entry of "Roger Ebert's Journal" online Tuesday night he is taking a "leave of presence" from his day-to-day work.
"The 'painful fracture' that made it difficult for me to walk has recently been revealed to be a cancer. It is being treated with radiation, which has made it impossible for me to attend as many movies as I used to," he wrote. "I'll be able at last to do what I've always fantasized about doing: reviewing only the movies I want to review."
Ebert began his stint as Chicago Sun-Times' film critic April 3, 1967. Famous nationally as the host of several movie-review TV programs, he had to slow down after a battle with thyroid cancer, which began in 2002. He has been unable to speak or eat solid foods for the past several years, due to complications from the disease and reconstructive surgeries.
The Chicago Tribune said Ebert had an operation after he fractured his hip in April 2008. He fractured it again this past December and has been undergoing treatment at the Rehabilitation Institute of Chicago since.