Detectives say the man walked into the KFC in the 9200 block of Roosevelt Boulevard at 6:50 p.m. on November 8th.
Surveillance video shows him wearing a bandana handkerchief over his nose and chin while pointing a handgun at workers and demanding money.
Police say rather than comply, the workers fled out the back door.
When the gunman saw that, he also took off - without taking any money.
Detectives are looking for a white man, about 20 years old, 6'2" tall, 200 lbs with a thin build.
He was wearing a black and white bandana over his face, a gray sweatshirt and black pants.
Anyone with information is urged to contact Philadelphia Police at 215-686-TIPS (8477), text a tip to PPD TIP (773847) or through PhillyPolice.com.