Enzyme activities and some other properties of sake koji made from three cultivars (Gohyakumangoku, Nipponbare and Tsukushihomare) of rice by using various seed-koji were examined. Some differences in enzyme production and the activity ratio of glucoamylase/acid carboxypeptidase were recognized among koji from three rice cultivars with various seed-koji. The koji from Gohyakumangoku showed higher enzyme production and higher ratio of glucoamylase/acid carboxypeptidase than koji from other rice cultivars. Qualities of koji from Nipponbare and Tsukushihomare could be improved by selecting seed-koji. The mycelial distribution in koji and the color of koji were varied with the strain of seed-koji. It was considered that these features of koji were concerned in the quality of koji. Fatty acid composition and amino acid composition of the koji were also varied with the strain of seed-koji. It was considered that differences in these components of the koji contributed to the quality of sake.