The effect of concurrent affective and alcohol use disorders on suicidal ideation and behavior was investigated. The Diagnostic Interview Schedule Version III-R (DIS) was administered to 307 adult veteran men ranging in age from 23 to 78. Participants were classified into one of four groups based on their final DIS diagnosis-lifetime unipolar depression and lifetime bipolar I disorder with or without a lifetime alcohol use disorder. Logistic regression analyses indicated that veterans with a major affective disorder were at greater risk for suicidality than veterans without an affective disorder. However, veterans with unipolar depression were at no greater risk for suicidality than those with bipolar I disorder. Unipolar and bipolar I disorders with a concurrent alcohol use disorder were always associated with an increased risk for suicidality.