The biological similarities of four coastal prehistoric populations of Arica are compared with coastal and highland groups of Peru and Bolivia. A statistical analysis based upon five craniometric measurements indicates that the groups of Arica are closely related to highland populations, particularly one group from the Urubamba valley. The existence of similar cultural indicators between the coastal groups of Peru and Arica is explained on the basis of a highland center from which cultural traits diffused to the Peruvian and Chilean valleys. -- AATA