The objective of this research was to determine the prevalence of retrospectively recalled childhood trauma among depressed patients and to examine the relationship between retrospective recall of childhood maltreatment and the onset, course, and severity of major depression in adulthood. Forty-seven adults with DSM-IV major depression and forty-one healthy comparison subjects were administered the Childhood Trauma Questionnaire (CTQ), a self-report measure of traumatic experiences in childhood. Age at onset of first depressive episode, number of lifetime depressive episodes, current depressive severity, and presence of lifetime anxiety and substance use comorbidity were determined for the depressed patients using the Structured Clinical Interview for DSM-IV. Patients with major depression recalled significantly more severe emotional abuse, emotional neglect, and physical abuse than the healthy comparison subjects. Among the depressed subjects, the severity of childhood trauma (most notably emotional abuse) predicted 25-28% of the variance in age at onset of first depressive episode (earlier onset) and number of lifetime depressive episodes (more episodes). Depressed patients with recall of childhood trauma also experienced a significantly greater number of comorbid mental disorders (2.9 vs. 1.9) than depressed patients without trauma histories. The findings must be tempered by the possibility of a recall bias toward more adverse childhood experiences in the depressed patients. To the extent that these data are valid, they suggest that childhood maltreatment may influence the onset, course, and comorbid character of major depression.