The station attendant, 19, suffered injuries to his face after being punched by one of the robbers, Nassau County police said. Police said he was treated at the scene.
The robbery took place at 2:07 p.m., police said.
One robber pointed the gun at the clerk, while the other punched the teen in the face -- demanding he open the cash register. The robbers then stole cash and fled on foot.
Police said both robbers wore white T-shirts and jeans. The robber with the handgun also wore a white Kangol hat and a bandanna, police said.
Police ask anyone with information about the robbery to call Crime Stoppers at 800-244-TIPS. All calls will remain confidential.