Current trends in psychological research stress the role of family members in developmental studies, and this trend may be applied to the study of divorce and child custody in Japan. Japanese families are influenced by other social systems, including neighborhood and religious groups, and traditionally these systems have combined with relatives to support families with marital problems. However, the Japanese family has recently moved from the structure of the extended family to that of the nuclear family, and cohesive support networks are disappearing. At the same time, the Japanese divorce rate is rising. Reasons for the rise include: (1) a decrease in social pressures against divorce; (2) a weakening of the social support systems; (3) an improvement in the socio-economic conditions which follow divorce; and (4) the fact that the very large baby boom generation has reached divorceable age. Nevertheless, the Japanese divorce rate remains the lowest among developed countries, even though it is easy for most couples to get divorced. As for child custody, until the mid-1960s the father traditionally retained the child. Now more mothers are granted custody, often because the mother is able to financially support the child, while the father lacks the resources of an extended family. Joint custody is becoming more frequent, but is still uncommon. Family psychologists suggest that intervention and educational activities may be used to ease problems of children of divorce. (SKC)