The prevalence of consanguineous marriages was examined among the Arab rural population in the Western Galilee region in Israel. The survey was conducted by questioning women attending Mother and Child Health Centers, or those met on the main street of the village. The overall figures were unusually high (39%), including those for first and second cousins. They were highest in the Druze population (49%), lower in the Moslems (40%) and still lower in the Christians (29%) (P less than 0.001). The most common type was first-cousin marriages, especially where the husband's father and the wife's father were brothers. The prevalence of consanguineous marriages was higher in the younger generation whose members had remained in their family village. These findings indicate that the traditional way of life, with its close family relationships, is still most common in the Arab rural society in Israel. The high prevalence of consanguinity is an unfavorable factor in this population's health condition. It is believed that the present educational and occupational changes will gradually alter this custom.