According to a News 12 Long Island report, a man with a gun entered the shop and demanded cash. It was unclear how much money was taken from the store.
Police did not release a description of the assailant. No arrests have been made.
Canine officers, detectives and crime scene investigators were at the smoothie shop for several hours after the robbery. Police officers were also seen removing several evidence bags from the scene.
Authorities said the incident is under investigation. A law enforcement source said the case has been assigned to detectives in the Pattern Crimes Unit. A supervising detective in that unit did not immediately return a call for comment.
Anyone with information about the crime is encouraged to call Suffolk County Crime Stoppers at 1-800-220-TIPS.