The effects of parental divorce during childhood and adolescence on the mental health of young adults (age 23) were examined, using the National Child Development Study (NCDS), a longitudinal, multimethod, nationally representative survey of all children born in Great Britain during 1 week in 1958 (N = 17,414). Children were assessed at birth and subsequently followed up at ages 7, 11, 16, and 23 by means of maternal and child interviews, and by psychological, school, and medical assessments. Parental divorce had a moderate, long-term negative impact on adult mental health, as measured by the Malaise Inventory total score, and controlling for economic status, children's emotional problems, and school performance preceding marital dissolution. The likelihood of scoring above the clinical cutoff of the Malaise Inventory rose from 8% to 11% due to parental divorce. This indicated that the relative risk of serious emotional disorders increased in the aftermath of divorce, but that the large majority of individuals did not exhibit such risks. Path analyses revealed that the negative effects of divorce on adult mental health operated indirectly through higher emotional problems and lower levels of school achievement and family economic status at age 16. Results related to timing of divorce, remarriage, and interactions between age 7 emotional problems and divorce, and between age 7 emotional problems and child gender, are also discussed.