ESPN reported the diagnosis Wednesday afternoon.
"I've always believed life is about embracing the gifts and rising up to meet the challenges," Schilling said in a statement released by ESPN. "We've been presented with another challenge, as I've recently been diagnosed with cancer."
"Our thoughts are with Curt and his family during this challenging time," the network said in a statement. "His ESPN teammates wish him continued strength in his cancer fight and we look forward to welcoming him back to our baseball coverage whenever he's ready."
ESPN writes, "Schilling, 47, pitched in the majors for 20 seasons for the Baltimore Orioles, Houston Astros, Philadelphia Phillies, Arizona Diamondbacks and Boston Red Sox. The six-time All-Star finished with a record of 216-146 and a 3.46 ERA. His 3,116 strikeouts rank 15th all time."
Schilling was a member of the Phillies from 1992 to 2000, including the 1993 National League Championship team.
He won two World Series titles with the Red Sox in 2004 and 2007. Schilling also won a title as a member of the Diamondbacks in 2001, when he shared MVP honors with fellow starter Randy Johnson.
In December, ESPN announced that Schilling would be part of its "Sunday Night Baseball" broadcast team for the upcoming season. It also announced a multiyear contract extension with him.
ESPN did not say what Schilling's broadcast plans will be for the upcoming season.
ESPN.com contributed to this article