Detectives said the man was 5 feet, 7 inches tall, between 20 and 25 years old, and wore dark clothing and a dark cloth that covered part of his face.
At 3:15 a.m. the suspect struck again at a Mobil station at 1021 Northern Blvd, Flower Hill. This time, he showed a black handgun, and an attendant gave him an undetermined amount of money, police said.
He apparently made his last stop 45 minutes later, holding up a Mobil at 595 Northern Blvd. in Great Neck, where he got an undetermined amount of money, police said.
Police said the man left each gas station on foot.
No injuries were reported.
Police ask that anyone with information regarding these crimes call Nassau County Crime Stoppers at 800-244-TIPS. All callers will remain anonymous.