The shooting happened at the Loop Inn on Routes 1 & 9 and Rodgers Street around 5 a.m.
One victim was injured and taken to University Hospital in Newark, where he is listed in critical condition. The other victim was pronounced dead at the scene around 5:30 a.m.
Several people were being questioned, but so far, no arrests had been made.
The incident started possibly as an attempted robbery, officials said.
The Middlesex County Prosecutor's Office is investigating.
Anyone with information about the case is asked to call (732) 634-7700, or (732) 745-4436.