A man suffered a serious head injury after a fight in Needham Market High Street just after midnight.
Police were called to reports of a group of men fighting in the street.
Two men were assaulted during the incident. A man in his 60s received minor injuries and was taken to West Suffolk Hospital. Another man in his 30s, suffered a serious head injury and was taken to Addenbrookes where his condition was said to be stable.
Police say the suspects were white white men wearing dark, hooded tops, and one featured white writing on the back.
A cordon was put in place around the scene while officers carry out enquiries.
Police are appealing for anyone who witnessed the incident which happened around 12.15am or anyone with information to contact them on 101.