Although most studies on sleep in child and adolescent depression have indicated that sleep is relatively unaffected, abnormalities have been found. We hypothesized that discrepancies occur because family history of depression and sleep abnormalities in a parent have not been taken into account. In a group of parents and offspring with a family history of depression, 57% of parents had evidence of abnormal sleep. Sleep continuity and sleep architecture were correlated, and the magnitude of these correlations increased between parents with abnormal sleep and their offspring. Abnormal sleep may be expressed at a younger age when there is familial evidence for depression and abnormal sleep in a parent.