But the singer, who's famous for his monstrous proboscis, is maintaining his typical self-deprecating humor about the injury.
"I veered to the left instead of the right and slammed right into the wall," Manilow said. "I may have to have my nose fixed and, with this nose, it's going to require major surgery."
The 56-year-old singer said Tuesday that he'd returned to his Palm Springs home after spending two weeks in Malibu working on longtime friend Bette Midler's upcoming Rosemary Clooney tribute album.
In the middle of the night, he awoke disoriented and walked into a wall. He passed out for four hours after the accident but was OK, his manager said.
Manilow, whose hits include "Copacabana," "Mandy" and "Tryin' to Get the Feeling Again," said he'll seek a doctor's advice about whether to have surgery.