Mice from various inbred strains consume alcoholic beverages at highly reproducible and strain–specific levels. While most mice consume alcohol in moderate amounts, C57BL/6J animals exhibit sustained oral ingestion of high levels of alcohol in the presence of competing water and food. We now report a genetic investigation of this phenotype as one potential model for alcoholism. An intercross–backcross breeding protocol was used to identify two recessive alcohol preference quantitative trait loci (QTLs) that are both sex–restricted in expression. A comparison of our results with those of an earlier morphine preference study argues against the hypothesis of a single unified phenotype defined by a preference for all euphoria–producing drugs.