Many countries in South Asia, including Nepal, India and Bangladesh, demonstrate a strong cultural preference for sons, which may influence fertility desires and contraceptive use. METHODS: Demographic and Health Survey data from married, nonpregnant women aged 15-49 who had at least one child were used to examine the relationship of parity and number of sons to reproductive outcomes in Nepal, India and Bangladesh. Outcomes of interest were desire for another child, contraceptive use and type of contraceptive (modern vs. traditional, temporary vs. permanent). Odds ratios and relative risk ratios were calculated using binary and multinomial logistic regression. RESULTS: In general, desire for another child decreased and contraceptive use increased as the number of children and number of sons increased. These associations were more prominent in Nepal and India than in Bangladesh. For example, compared with women who had three daughters and no sons, the odds of contraceptive use among women with two sons and one daughter were 4.8 in Nepal, 3.5 in India and 2.0 in Bangladesh. Within India, the associations of parity and number of sons with reproductive outcomes were generally stronger in northern states than in South India or West Bengal.