Police are speaking to two men after a man was found unconscious in Northbridge this morning.
The men, aged 26 and 20, are assisting police with their investigation into the discovery of the 29-year-old man on the footpath in Lake Street at about 2.15am.
Police believe the man was involved in an argument with three other men before he was struck to the face and fell backwards, hitting his head on the footpath.
The man was taken to Royal Perth Hospital for treatment.
Police have urged anyone with information on the incident to contact Crime Stoppers on 1800 333 000.