An elderly man jumped to his death from a high-rise in Chelsea, cops said Sunday.

The 75-year-old victim was found dead in front of 280 Ninth Ave., a 21-story building, just after 11 p.m. Saturday.

“We were just watching a movie, and all of a sudden, we saw something flying past the window,’’ said a 16th-floor resident who declined to give his name.

“Then a couple of seconds later, we heard the boom.”