The first robbery occurred at the Wilmington Savings Fund Society Bank at 11:30 a.m.
The bank is located inside the Safeway Supermarket on Foulk Road.
Police say the robber displayed a small handgun and left with an undisclosed amount of money.
About a half hour later, another robbery took place at the TD Bank on the 1800 block of Marsh Road.
The description of the suspect is the same in both cases.
The suspect is described as a black male in his 20's, 5'7, and medium build. He was seen wearing a light brown puffy jacket and a light brown baseball cap.
No gun was displayed in the second robbery.