Sixteen strains of cellulolytic yeasts and yeast-like microorganisms were isolated from natural materials collected in Japan by enrichment technique. Seven of them belonging to ascomycetous anamorphic yeasts, an ascosporogenous yeast and an yeast-like genus Prototheca were classified into five species, Candida cellulolytica sp. nov. (1 strain), Candida fukuyamanensis sp. nov. (1 strain), Candida krusei (3 strains), Williopsis saturnus var. saturnus (1 strain) and Prototheca zopfii (1 strain). Candida cellulolytica has Q-7 as the major ubiquinone and 41.6mol% of G+C in DNA, and is assumed to have a glucan-mannan type cell wall, and C. fukuyamanensis has Q-9 as the major ubiquinone and 47.8mol% of G+C in DNA, and is assumed to have a glucan-mannan type cell wall. Descriptions of two new Candida species are given.