The victims were shot inside the Good Day Deli Grocery at Westchester Avenue and Wheeler Avenue just before 2 a.m.
An 18-year-old was shot in the head and pronounced dead at the scene. A 19-year-old was shot in the torso and rushed to Jacobi Medical Center, where he is in stable condition.
The gunman fled the scene, possibly in a taxi cab he hailed.
No arrests were made, and there was no immediate motive.