The incident happened on Wednesday around 1:30 p.m. at the Hilton Home 2 Suites Hotel on the 1200 block of Arch Street.
Police say a 34-year-old Canadian man was staying at the hotel for an education conference.
The victim met an unknown male on Grindr, an LGBT website.
The victim invited the man to his hotel room. Upon arrival, the suspect told the victim that he had a gun and proceeded to sexually assault him.
Police say the suspect also forced the victim to withdraw a total of $1,000 from various ATMs. The victim also was forced to purchase $2,000 in VISA gift cards.
A short time later, the suspect and the victim went to the Irish Pub at 20th and Walnut streets, where the victim was able to escape.
The suspect also fled on foot. He is described as a black male in his 20s. He's approximately 5'11", with wavy hair and star tattoos on the back of his right hand. He was last seen wearing a dark colored jacket, dark blue jeans with rips, and tan Timberland boots.
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.