An analysis of the changing structure of causes of death in the city of Lagos between 1965 and 1975 was conducted. Registered deaths from the vital statistics system of the Lagos State Ministry of Health were employed. It was found that significant changes in causes of death among the population had occurred during the period. In the 1960s, diseases which killed children were more common than those which killed adults. The most significant feature of these fatal children diseases was the sharp contrast between the causes peculiar to neonates (perinatal) on the one hand and those common among post-neonates and pre-school-age children on the other. Commencing around 1970, however, children-related causes ameliorated considerably and the proportion of adults dying then became the higher. The most important cause of death during this period was accidents. The gap between male and female deaths from accidents is explained not only by different roles and behaviour of the sexes but also by men's obsession with high-risk vehicles. But this safety which women enjoyed was countered by increasing mortality from pregnancy complications, a phenomenon associated with higher gravidity in the 1970s.