A survey of deaths occurring in women in association with pregnancy and childbirth was carried out in a large mission hospital in Benin City, Nigeria, with a view to identifying the underlying biosocial factors that influence such deaths. Age, parity, booking status, level of educational attainment and socio-economic status were all found to be important variables statistically affecting maternal death risks. No significant association was found in the study between maternal death risks and other social variables such as marital status, distance of home from hospital and ethnic origin of pregnant women. Maternal deaths were shown to be an index of the socio-economic standards in any society, and measures to lower the present high rates of maternal mortality in Nigeria and other developing countries through a manipulation of these biosocial factors were highlighted.