The 4 1/2-year-old son of the rock guitarist Eric Clapton was killed yesterday morning when he fell out an open bedroom window on the 53d floor of a Manhattan apartment building.

The boy, Conor, who was dressed in red pajamas and slippers, landed on the roof of a four-story building next to Galleria Condominiums, a 57-story building where the boy was staying with his mother, the police said.

They said the window, about 6 feet high and 4 feet wide, was left open after it was cleaned by a housekeeper. The boy, who was not in the room during the cleaning, darted past the housekeeper and somehow fell out the window, which was not protected by a window guard, the police said.

"At this point it seems as if this was a tragic accident," said a police spokesman, Capt. Stephen Davis.