Distribution and movement of marked oriental cockroaches,Blatta orientalisL., were studied at four apartment buildings during the summers of 1984 and 1985. Porches were the primary cockroach harborage sites during the summer. In a mark/recapture study, 50% of marked, resighted cockroaches remained at one porch, 35% moved within an area on one side of a building, 13% moved between the front and back of a building, and 2% moved between buildings. Only 2% of these resighted cockroaches moved indoors.