Very little is known of the biology, culture and history of the several tribes living in densely concentrated villages and kraals along the Okavango River, the international boundary between Angola and Namibia (South West Africa). The blood group distribution among the Kuangali, Bunja, Mbukushu and Kwengo tribes is presented. A significant cline in ABO groups down the river is not detected. The frequencies of haptoglobins and transferrins in the Kuangali and some Kung Bushmen are given. The study highlights the common origin of these territorially separated tribes and the probable historical gene exchange among them based on identical cultural traditions. Keywords: ABO blood groups, cline, Okavango tribes, Black Bushmen, haptoglobins, transferrins.