It happened at the Clearview Bala Theater on Bala Avenue at 8:00 p.m. Monday.
Police say two suspects approached a worker in the office area, roughed up the employee and made off with between $1,000 and $1,500 in cash.
One of the suspects is described as a black male, 5'9", thin build, with facial hair. He was last seen wearing a black sweat shirt with a hood and tan pants.
There is no description yet on the second suspect.
Police are looking surveillance video hoping it leads to additional details about the suspects.
The worker was treated at the scene for minor injuries.