Available evidence suggests women may be more vulnerable to the effects of chronic alcohol consumption than men. The few investigations of gender differences in treatment-seeking populations have often involved study samples restricted by selection criteria (e.g., age, education). The current study examined gender differences in a heterogeneous sample of individuals seeking treatment for a substance use disorder. We examined alcohol drinking levels, age at drinking milestones (e.g., first drink, first intoxication), and progression from milestones to alcohol problems or treatment. Additionally, family history, spousal alcoholism, and nicotine use were analyzed.