The body of the man, who is in his 70s, was discovered in a house on Greenisland’s Station Road around 9.30 pm last night.
The PSNI say a post mortem examination is due to take place to determine the exact cause of death.
A 29-year-old woman and two men, aged 23 and 24, have been arrested over the death.
As a result of the death, Station Road has been closed between the junction of Upper Station Road and School Lane and Knockfergus Park while a forensic examination of the scene is carried out.
Police have said it is likely to remain closed for some time.