Daniel Stephen, 38, was last seen at his home in Peachey Drive, Thatcham, at 10pm on Tuesday, but his partner awoke the next morning to find him gone.
He is white, 6ft 6ins tall and of medium build with short brown hair. Before he disappeared he was wearing a hooded top, blue jeans, and brown boots.
He drives a 56 plate beige Skoda Roomster 2 and officers think he may be in the Devon, Dorset or Hampshire area.
Anyone who has information on his whereabouts should contact police on 101.