The author examined the relationship between symptom criteria for major depression and family history of mood disorders in 82 outpatients with major depression and 27 outpatients with nonaffective disorders. The family members of depressed patients with six or more groups of DSM-III symptoms of major depression exhibited substantially higher rates of mood disorders than the family members of depressed patients with fewer than six groups of symptoms and the family members of patients with nonaffective disorders. These data suggest that stricter symptom criteria for major depression may define a more homogeneous phenotype, at least from the standpoint of familial aggregation.