BACKGROUND Although depression is common among alcohol and tobacco dependent patients, its impact on treatment outcomes is not well established. The purpose of this study was to examine the impact of depressive symptoms on abstinence from tobacco and alcohol after treatment for alcohol dependence and nicotine dependence. METHODS The Timing of Alcohol and Smoking Cessation Study (TASC) randomized adults receiving intensive alcohol dependence treatment, who were also smokers, to concurrent or delayed smoking cessation treatment. The sample consisted of 462 adults who completed depression and substance use (alcohol and smoking) assessments at treatment entry and 6, 12, and 18 months posttreatment. Longitudinal regression models were used to examine the relationships between depression and subsequent abstinence from alcohol and tobacco after baseline characteristics, including alcohol and smoking histories, were considered. RESULTS Depressive symptoms were prospectively related to nonabstinence from alcohol. Depressive symptoms at the previous assessment increased the odds of drinking at the subsequent time point by a factor of 1.67 (95% CI 1.14, 2.43), p < 0.01. Depressive symptoms were not significantly related to subsequent abstinence from cigarettes. CONCLUSIONS Depression is an important negative predictor of the ability to maintain abstinence from alcohol within the context of intensive alcoholism and smoking treatment. It may be important to include depression-specific interventions for alcohol and tobacco dependent individuals to facilitate successful drinking treatment outcomes.