The relationship between a history of attempted suicide and prior course of illness was explored in 87 patients with major affective disorder. Fifty-eight percent of bipolar (n = 67) and 50% of unipolar (n = 20) patients had a history of a suicide attempt. Females were more likely to have made an attempt (67%) than males (42%) and were equally likely to have made a violent attempt. Course of illness and prior history of psychosis were similar in patients with and without a history of an attempt. However, in patients who made an attempt, the severity of the worst attempt was positively correlated with the duration of illness. Greater numbers of prior attempts were associated with greater lethality of the worst attempt. Suicidal ideation for the period of most severe depression in the prior 12 months did not correlate with any measure of lethality of suicide attempt. These data not only suggest the need for further studies of suicide in relationship to the longitudinal course of affective illness, but also the need for continuous reappraisal of suicidal risk in patients with recurrent affective disorders.