OBJECTIVE: To examine whether mental health service utilization modifies the association between lifetime anxiety or depressive disorders (ADD) and risk of 12-month problematic alcohol use. METHODS: Randomly selected members (n=6518) of a mutual health-insurance company were evaluated for lifetime ADD (DSM-IV), mental health service utilization for ADD, and risk of 12-month problematic alcohol use (DSM-IV and CAGE). RESULTS: Risk of 12-month problematic alcohol use was reduced when mental health services had been used for several ADD (OR=3.3 vs 5.8), but not for one ADD. CONCLUSIONS: These results show the importance of taking mental health service use into account as a potential effect-modifier of psychiatric comorbidity.