A 38-year-old man needed 17 stitches to the head when he was attacked and robbed in Nottingham, police have said.
Officers said the man was assaulted by four youths as he was walking home with his wife on Whitegate Vale, Clifton, in the early hours of Saturday.
He was repeatedly punched in the head leaving him unconscious. The offenders then pulled jewellery from his body.
The man was taken to the Queen's Medical Centre and later released. Police have appealed for witnesses.
Det Sgt Leigh Sanders, of Sneinton CID, said: "This was a very nasty robbery. The victims had enjoyed a night out and were walking home when a gang confronted them.
"The husband has then been subjected to a vicious, unprovoked attack. His wife was not injured but she watched her husband being assaulted and she is extremely shaken and upset."
The attackers are described as black, aged between 19 and 20, and wearing dark clothing with hooded tops.
Three men have been arrested in connection with the incident but were released on bail.