Southwark Police are appealing for any witnesses or information concerning a stabbing at London Road, Elephant and Castle, on Tuesday 10 June.
The man, aged 34, was taken to hospital suffering from stab wounds. He remains in hospital where his condition is said to be stable.
The incident is being investigated by Southwark CID.
DC Ashley Kean says the area where the stabbing occurred is a very busy part of Southwark, linking St George's Circus with the Elephant and Castle roundabout.
"There would have been many people walking around the area as well as getting on or off buses near the location of the incident.
"We believe the suspect is a man in his 20s, possibly Asian, and described as 'scruffy' in appearance. The victim is a white man. It's possible the two men had been involved in an altercation before they arrived in London Road."
There have been no arrests and police are continuing their investigations.
The number to ring with any information is Southwark CID on 020 7232 6222 or Crimestoppers on 0800 555 111 to remain anonymous.