Dysplasia of the hip is almost unknown in the Bantu peoples of Africa, except in cases of arthrogryposis and in those with partly European ancestry. Evidence is produced to show that the importance of intrinsic genetic factors in hip dysplasia far outweighs that of the extrinsic factors. These are of great importance only if allowed to act on a hip in which genetic factors have already determined dysplasia. Evidence is also produced to contradict the theory that the "piggyback" carrying method used by Bantu mothers is the reason for the immunity from dysplasia of the hip. The absence of "primary" osteoarthritis of the hip is noted, and the range of hip disorders leading to "secondary" osteoarthritis in the adult African is compared with that in the adult European. Three patients are described, one in each of the groups mentioned above, the third having an isolated "typical" congenital dislocation of one hip. The methods of study used were enquiry into obstetric history and into carrying methods, and arthrography to confirm clinical findings. The experience of other surgeons working in Africa is recorded.