He took some food items up to the cash register, and when the 60-year-old cashier opened the register drawer, the man attempted to reach in and grab some money.
The cashier tried to shut the drawer but the suspect pushed the woman to the ground and got away with some fistfuls of cash.
The Suspect is described as a white male, 5'6" to 5' 8" tall, late 20's to early 30's, tattoos on his fingers, wearing a black jacket with red stripes and a black baseball cap with the letter "B" inscribed on the front.
He possibly entered a green Honda Civic after the robbery.
Detectives also believe that there were several witnesses outside the Walgreens as the suspect fled.
Police are asking any witnesses to contact the Second Squad at 516-573-6253 or Crime Stoppers at 1-800-244-TIPS.
They believe this incident may be related to a robbery that happened Thursday at the Rite Aid on Larkfield Road in East Northport.
A 91-year-old clerk was held up and injured in during that robbery.