On October 12, 1930, Diamond was shot and wounded at the Hotel Monticello on the west side of Manhattan. Two men forced their way into Diamond's room and shot him five times before fleeing. Still in his pajamas, Diamond staggered into the hallway and collapsed. When asked later by the New York Police Commissioner how he managed to walk out of the room, Diamond said he drank two shots of whiskey first. Diamond was rushed to the Polyclinic Hospital in Manhattan, where he eventually recovered. On December 30, 1930, Diamond was discharged from Polyclinic.