The man, 46, was discovered outside a home on the Strand Road area of Coleraine at about 3.50am today.
Police said two people have been arrested.
The man was taken to hospital for treatment to head injuries but was pronounced dead a short while later.
COMMENT RULES: Comments that are judged to be defamatory, abusive or in bad taste are not acceptable and contributors who consistently fall below certain criteria will be permanently blacklisted. The moderator will not enter into debate with individual contributors and the moderator’s decision is final. It is Belfast Telegraph policy to close comments on court cases, tribunals and active legal investigations. We may also close comments on articles which are being targeted for abuse. Problems with commenting? email@example.com