The study reported here explored the influence of maternal, health care, pregnancy, and child-related factors upon the duration of total breast-feeding (DTBF) in the Dominican Republic. The data for the study, which included 1984 mother-child pairs representative of the Dominican population, came from the National Health Survey of 1991. The child in each of the mother-child pairs was the mother's last-born child who had been breast-fed and was less than 3 years of age at the time of the survey. Interviews with the mothers were used to collect information about the duration of breast-feeding and the factors studied (including maternal age, urban/rural residence, parity, mother's socioeconomic status, maternal education, maternal employment, mother's desire for pregnancy, type of delivery, place of delivery, the type of health worker attending the delivery, the child's sex, the child's birth weight, the time elapsed between delivery and initiation of breast-feeding, the child's age at complete weaning, and the child's age at the time of the survey). The child's risk of complete weaning at different ages was calculated using the life table method, and the independent effect of each of the study variables was estimated using Cox's regression model. The median DTBF was 7 months. The risk that a child would be completely weaned (the relative rate of complete weaning, or RRCW) was found to be higher among children who received foods other than breast milk and water while still breast-feeding (RRCW = 8.56; 95% CI = 4.25-17.20), whose mothers had some university education (RRCW = 1.48; 95% CI = 1.24-1.77), who began breast-feeding a day or more after delivery (RRCW = 1.25; 95% CI = 1.11-1.40), who were born in either public health institutions (RRCW = 1.62; 95% CI = 1.24-2.11) or private health institutions (RRCW = 2.19; 95% CI = 1.65-2.91), and who were the first-born of mothers with low socioeconomic status (RRCW = 1.80; 95% CI = 1.45-2.24). According to the study results, the country's breast-feeding programs should give special attention to mothers with university educations, those giving birth in private health facilities, and those with low socioeconomic status giving birth to their first child, since these groups tended to breast-feed their children for relatively short periods of time. Also, breast-feeding promotion strategies should stress the importance of delaying the introduction of foods other than breast milk into the child's diet, as this appears to be the one factor having the greatest adverse effect on the duration of breast-feeding.