A large fight broke out in the early hours of yesterday in Wandsworth Road near the junction with Lavender Hill.
Officers say they are working to inform the 24 year old man’s next of kin.
They are also awaiting an update on the condition of the man who was taken to hospital, while a third was discharged.
Detective Chief Inspector Stephen Payne, said: “One man has lost his life and two others have been treated in hospital for their injuries.
“My team has been working around the clock to establish what happened and our enquiries remain ongoing.
“I am today appealing for anyone who was in the area of Wandsworth Road in the early hours of Sunday to come forward and speak with us. It is possible that you may have seen something that can help us identify those responsible.
“I would also ask that people check their dash cam or any private CCTV to see if you captured any part of the attack, or anyone running away.”
Chief Superintendent Seb Adjei-Addoh, who is in charge of policing in Lambeth, said: “Our thoughts are with the family of the young man who has lost his life in the most tragic of circumstances.
“We are working closely with our colleagues to ensure that arrests are made as quickly as possible.
“I know the local community will be shocked by these events. You can expect to see officers in the area and I would encourage anyone with concerns, or information, to please speak with them.”
Anyone with information is asked to call police on 101 quoting CAD 1169/29Sep. Alternatively you can contact the independent charity Crimestoppers on 0800 555 111 or visit crimestoppers-uk.org.