In the case of sake, ethyl caproate and isoamyl acetate are considered to be closely associated with flavor. Various mutant yeast strains producing a higher Level of flavor compounds (ethyl caproate and /or isoamyl acetate) than the parent strain were isolated by ethyl methane sulfonate treatment followed by global selection. Two of the mutants obtained also showed a high malate productivity. These mutants would be promising for practical sake fermentation.