Alcohol dehydrogenase genes show polymorphism. gamma subunits, which are encoded by ADH3 genes, have two subtypes according to the single base substitution of codon 271 and 349. This mutation of codon 271 directly determines subtypes with different catalytic properties. However, there has been no simple technique to detect nucleotide changes at codon 271. Specific amplification of nucleotides around codon 271 was difficult because of homologous nucleotide sequences around the region among 3 ADH genes (ADH1, 2 and 3). We have developed a method to amplify the ADH3 gene alone with a modification on 3'-end of primer by polymerase chain reaction. Approximately 200 nucleotides including codon 271 of ADH3 gene were sequenced, and genotypes of ADH3 gene were determined in 30 Japanese individuals. This method may facilitate the studies on racial differences of genotypes and involvement of ADH genes in patients with alcoholic liver disease.