During the first half of the twentieth century, Portuguese Colonial anthropology was almost completely centered in biological anthropology. The so called «Escola do Porto» («Oporto School») founded by the well reputed Doctor of Medicine, Professor Mendes Correia, conducted all the Overseas «Anthropological Missions», officially institutionalized by the colonial government. The most well succeeded Research Campaign was coordinated by one of his disciples, Santos Júnior, who was also a Doctor and Lecturer at the Oporto Faculty of Medicine. Between 1937 and 1956, Mozambique Anthropological Mission carried out an extensive anthropometric survey of the African populations from the colony. Ethnology, or basically ethnographic collection, was disregarded, left in the hands of curious dilettantism of the several colonial officers, missionaries, soldiers, administrative technicians, merchants and landowners. The important role assigned to Biological Anthropology in relation with Portuguese colo­nial enterprise is the central issue addressed in this paper. And subsequently, trying to under­stand why, during the second half of the twentieth century, was Biological Anthropology so suddenly substituted by Colonial Ethnology.