Carey tweeted that Cannon is suffering from "mild kidney failure." His representative confirmed Cannon's hospitalization. He is in Aspen, Colo., where he and Carey were vacationing.
Carey posted a picture on her website of a miserable-looking Cannon in a hospital bed as she lay beside him. She asked for prayers and said Cannon's situation was "very painful." She later called it a "serious moment that's very tough on all of us."
The pair became the parents of twins -- a boy and a girl -- last year.
Cannon is 31. His representative had no further information Wednesday about his condition, but said he is still hospitalized.