Officers were called to an address in Eastleigh at around 10.15pm on December 21 where they found a 23-year-old man with a serious head injury who was subsequently taken to hospital.
Police arrested a 17-year-old man and a 17-year-old woman, both from Eastleigh, on suspicion of attempted murder while a 48-year-old man, from Bursledon, has been arrested on suspicion of GBH.
They all remain in custody.
A police spokesman said: '˜We were called to Heinz Burt Close, Eastleigh at around 10.15pm, following reports that a man had been seriously injured.
'˜A 23-year-old man, from Winchester, was found inside an address with a serious head injury.
'˜He was taken to Southampton General Hospital, where his condition is described as life-threatening.
'˜His next of kin have been informed.
Anyone with information that may help the investigation is asked to call 101, quoting 44180474032.