Dyfed-Powys Police is concerned for the welfare of Geraint Griffiths, aged 30, who has been missing from his home in Llandrindod Wells since the early hours of Monday, November 20.
He is described as around 5ft 9in tall, of slim build, with short brown hair, and has several tattoos – a sleeve on one arm and a dragon on the other.
He is believed to be wearing blue jeans, a grey jumper, black coat and a woollen hat.
Anyone who has seen Geraint, or has information that could lead to his whereabouts, is asked to contact Dyfed-Powys Police on 101.