The incident unfolded at about 2:30 a.m. Sunday as the man was walking back to his house in the 2200 block of E. Olive Street, said Seattle police spokeswoman Renee Witt.
The victim was listening to music over his headphones when suddenly he was struck in the back of his head by a blunt object, knocking him to the ground.
When he looked up, the two robbers were standing over him. One of them was pointing a shotgun at the victim's face.
The suspect then struck the victim in the face with the shotgun several times. The robbers forcibly took the victim's cell phone and wallet and fled the scene.
The victim walked home and called 911 from his house. Police responded and searched the area with a K-9 police dog, but they could find no sign of the suspects.
The victim sustained lacerations requiring stitches to the back of his head and under his left eye.
Anyone with information about the suspects' whereabouts is asked to call 911. Anonymous tips are welcome.