In a case-control study, a sample of post-neonatal deaths from pneumonia occurring in the Metropolitan Area of Rio de Janeiro, Brazil (1986-1987) were compared with healthy controls who lived in the same neighborhood. Risk factors investigated were variables related to the mother's pregnancy history and the child's birth, to the family's social condition and to the use of health services. Using the univariate logistic regression model, the coefficients of each independent variable, the relative risk and its confidence limits were first estimated. Birth weight and age of weaning were strongly associated with the dependent variable. After adjustment by means of the multiple logistic regression model, only 4 variables remained statistically associated with mortality: age of weaning, birth weight, over crowding, and BCG vaccination. Based on the available data, it was concluded that mortality from pneumonia in children under 1 year of age is significantly related to the social condition of the family, particularly to that of the mother.