The 33-year-old was the victim of a “violent attack” after leaving a friend’s flat in Paisley, Renfrewshire, on Friday to go out in the local area.
Police said the man left the flat in Argyle Street at around 6.30pm and returned around 1.20am on Saturday having suffered a stab wound and a head injury.
He was taken to the town’s Royal Alexandra Hospital, where medical staff describe his injuries as life-threatening.
Police are treating the incident as attempted murder and appealed for information as they try to piece together what happened.
Detective Sergeant Ian Ross said: “Our enquiries are at an early stage and we are trying to establish the man’s movements after he left the flat on Friday evening.
“The man has suffered a violent attack and we need to piece together where he went and who he saw. This information will assist our investigation as we try to trace the person or people responsible for his attack.
“I am appealing to members of the local community to contact us with any information or knowledge they may have.
“It’s vital we find out exactly what happened to this man and why. Officers will be carrying out door-to-door enquiries in the area today and anyone with information is urged to pass it on.”
Officers are searching the area around Argyle Street to establish the location of the attack.
Detectives are also in the process of gathering any available CCTV footage for review.
Anyone with information can call officers at Paisley Police Office via 101 or call Crimestoppers on 0800 555 111, where information can be given anonymously.