It happened Wednesday night just before 11 o'clock at the Kingwood Exxon, 7600 Cantrell Road.
The suspects walked into the business and pointed a handgun at the clerk then grabbed money from the cash drawer. The men also took the clerk's cell phone, according to the incident report.
A man waiting in the store for the clerk to close the business told police he witnessed the robbery but the suspects never said anything to him or took anything from him.
Police describe the suspects as black men, 5'11", 150 pounds. One of them was wearing a black hoodie and blue jeans. The other had on a yellow and black hat and a grey hoodie.