Police and forensic teams have attended the scene of a sudden death in the Woodburn area of Carrickfergus on Saturday night.
Its understood the man who died was aged in his 40s. The PSNI said a post-mortem examination will take place to determine the cause of the death.
There are no further details at this stage.
UUP MLA John Stewart shared on Twitter that he had spoken with senior PSNI officers about the incident.
He said: "My thoughts are with the family and friends of the victim at this tragic time."