The gunman wore a white T-shirt covering his face.
Police said he walked into a 7-Eleven store at 1599 Hillside Ave. in New Hyde Park early Friday, told the clerk he had gun and demanded cash. He took the money and ran.
Now, Nassau County police are looking for him.
The armed robbery took place at 3:25 a.m. Police said a 28-year-old store employee was not hurt.
The robber was about 5-foot-9 with a medium build, police said. He wore olive green shorts, a black T-shirt with a gold stripe and flip flops. Police said that, despite announcing he had a gun, no weapon was seen during the crime.
Police are asking anyone with information regarding the incident to call to Crime Stoppers at 800-244-TIPS. All callers will remain anonymous.