An investigation is underway after the victims, aged 26, 37 and 39, were set upon by two men armed with knives in Southall Road in the Ashmore Park area of Wednesfield, as they left a public house on Friday night.
Emergency services were called to the area at about 10.55pm after many people in the area phoned 999 to report a fight between a group of people armed with weapons near the Gorse Road junction.
West Midlands Police said teams of officers, supported by firearms teams and paramedics, were immediately despatched to the scene.
A resident who did not want to be named for fear of reprisals said: "Just before 11pm I heard some shouting coming from the street. There were six people at the junction who sounded like they were trying to sort out a dispute. They were saying 'come on'.
"Then it just seemed to escalate out of hand and they were waving weapons around. One of the ones doing the attacking almost fell over on the kerb as he was hitting another man. The man who got attacked was just dripping in blood.
"It was a scary experience. You're not expecting to see something like that around here.
"If it had happened 20 minutes earlier the kids heading home from their school prom around the corner might have been affected because the police closed the road."
Several householders said they only became aware of the trouble when the police and ambulance vehicles arrived with flashing blue lights.
The three injured men, all from Wolverhampton, were taken to regional hospitals after sustaining multiple serious injuries and treatment for their life-changing injuries continues.
All three had just left a nearby pub when they were attacked.
The force said officers believed all of the men were known to each other.
Cordons were set up at the Southall Road junctions with Ecclestone Road and Griffiths Drive afterwards.
Officers want to speak to witnesses in the vicinity who saw the crime unfold, while investigators have started downloading CCTV and have looked at footage recorded on mobile phones. Forensic teams are also in the area searching for evidence.
Detectives were also actively searching for two suspects, who were described as wearing black clothes, and searches have been carried out at multiple addresses in the city.
Anyone with information is urged to contact the officers via the force's Live Chat (west-midlands.police.uk/contact-us/live-chat) quoting reference number 4513-240622 or telephone Crimestoppers on 0800 555 111 anonymously.