Police are becoming increasingly concerned for the whereabouts of 33-year-old Ryszard Stera.
He was last seen in the area of a bridge over the River Bann in Portadown at around 7.15pm last night (Tuesday).
He is described as having short black hair and was wearing, when last seen, white shorts, hat and black top.
Police want to hear from anyone who may know of his whereabouts or anyone who sees a male matching his description.
They are also asking members of the public who may see Ryszard not to approach him but to contact police in Lurgan on 101.