The data from the National Family Health Survey, 1992–1993, show that the extent of consanguinity is high (34.7 percent) in South India; 26.2 percent of women married close blood relatives, and 8.5 percent of women married distant blood relatives. A definite downward trend in the proportion of marriages between close blood relatives is observed. Education, age at marriage, religion and caste, and urban-rural childhood residence have significant independent effects on consanguinity. The multinomial logistic regression analysis reveals that in South India the downward trend in the proportion of marriages between close blood relatives is entirely explained by rising age at marriage and women's education over time.