OBJECTIVE Ethnic differences in alcohol consumption patterns are often reported in general population surveys, but less is known about variation among ethnic groups presenting for treatment. METHODS Within a larger clinical trial, patterns of drinking, drug use and related problems were compared for Hispanic (n = 102) and non-Hispanic white (n = 104) male (n = 154) and female (n = 52) clients presenting at a public clinic for outpatient treatment of alcohol problems. RESULTS Relatively few reliable ethnic differences were observed in alcohol /drug use patterns. Non-Hispanic white men reported significantly more pretreatment tobacco use than did Hispanic men (84.7% vs 61.3% of past 90 days). Hispanic women reported significantly fewer legal problems (28.6% vs 83.9%), symptoms of dependence and negative consequences of drinking relative to non-Hispanic white women. Measures of acculturation and acculturative stress failed to differentiate drinking patterns among Hispanic clients. CONCLUSIONS Within a treatment-seeking sample, Hispanics and non-Hispanics may be more similar with regard to drinking practices than is the case in the general population. High consumption, adverse consequences and dependence symptoms were characteristic of men presenting for alcohol treatment regardless of ethnic identification. In contrast, Hispanic treatment-seeking women had the lowest consumption, adverse consequences and dependence symptoms of all the groups described, and they reported significantly fewer alcohol-related problems and symptoms than did non-Hispanic women.