The incident happened just after 9 p.m. at the Wash and Play Laundromat on Lafayette Avenue.
Investigators say the pair pulled a gun on the clerk, who they then tied to a chair with duct tape.
They stole the cash register, $300, a cell phone, a personal check and the DVR security system.
The employee was not injured.
The man is approximately 35 years old, 5-foot-8 and 250 pounds with brown eyes and a goatee. He was last seen wearing a black jacket, black jeans, a black skullcap and black boots. He also possessed a silver semiautomatic pistol.
The woman is approximately 28, 5-foot-5 and 130 pounds with brown eyes and black hair in a ponytail. She was last seen wearing a black jacket, black jeans, a black skullcap and black sneakers.
Anyone with information in regards is asked to call Crime Stoppers at 1-800-577-TIPS (8477).