Coleraine police and the family of a missing 56 year old man say they're very concerned for his whereabouts.
John Thompson was last seen around midday on Saturday, August 20, in the Portstewart area.
He's described as 5' 10'' tall, with dark brown hair, and was wearing blue three quarter length shorts and a red raincoat.
Detectives believe he may have had a bike with him when he went missing.
They're appealling to Mr Thompson, or anyone who knows where he is, to contact Coleraine PSNI station on 101.