community studies of non-hospitalized children are essential to obtain a more thorough understanding of acute respiratory infections (ari) and provide important information for public health authorities. this study identified a total ari incidence rate (ir) of 4.5 per 100 child-weeks at risk and 0.78 for lower respiratory tract infections (lri). disease duration averaged less than one week and produced a total time ill with ari of 5.8% and for lri 1.2%. no clear seasonal variation was observed, the sex-specific ir showed a higher proportion of boys becoming ill with ari and lri and the peak age-specific ir occurred in infants of 6-11 months. correlation with risk factors of the child (breastfeeding, vaccination, diarrheal disease, undernourishment) and the environment (crowding, living conditions, maternal age and education) showed marginal increases in the rate ratios, making it difficult to propose clear-cuts targets for action to lower the ari and lri morbidity. the importance of an integral maternal-child health care program and public education in the early recognition of lri is discussed.