The test-retest reliability of a brief, easily administered questionnaire to assess family history of drinking problems was studied. Twenty alcoholic and twenty non-alcoholic volunteers completed the questionnaire on each of two occasions separated by about 2 weeks. The reliability of classification of first- and second-degree relatives as problem drinkers or alcoholics was examined, using both liberal and conservative diagnostic criteria. In general, both sets of criteria produced satisfactory test-retest reliability; one possible exception occurred when alcoholics' second-degree relatives were classified using the conservative criteria. The liberal criteria seemed to provide a more sensitive index of familial alcoholism.