Yeasts were isolated from mushrooms and fleshy Ascomycetes which were undergoing spontaneous decomposition. Samples of low pH usually yielded yeasts, those of high pH, rarely. The following yeasts were identified: Saccharomyces cerevisiae S. chodati, S. dairensis, S. disporus, S. heterogenicus, S. muciparis, Rhodotorula glutinis, R. colosteri, Cryptococcus sphaericus (Torula s.), Cryptococcus utilis (Torula u.), Cryptococcus californicus (Torulopsis californica), C. uvae and C. pulcherrimus.