The man, aged in his 30s, was found by police in Woodcross Court, off Hutson Street near St Luke’s Hospital, at about 1.20am today following a report of a disturbance.
He initially only appeared to have suffered facial injuries but after he was taken to hospital it was established that his condition was more serious.
A spokesman for West Yorkshire Police said the man was now “critical but stable”.
Two men, aged 51 and 44, have been arrested on suspicion of assault.
Anyone with information about the incident is asked to ring Bradford District CID on 101 or Crimestoppers anonymously on 0800 555111.