The effects of cultural temperature and nutritional components on the production of ethanol using juice of Pyrus serotina as the substrate for Saccharomyces cerevisiae ATCC 4124 were studied. After anaerobic cultivation in 5L flask of a defined pear juice at 2$0^{circ}C$, ethanol concentration of 11.5%(v/v) could be obtained. The addition of a small amount of K2S2O5 was essential for the successful production of ethanol. Ethanol concentration could be further enhanced by supplementing a small of various complex nitrogen sources. When 0.05% of yeast extract and 0.05% of (NH4)2HPO4 were added to a defined medium, ethanol concentration obtained after 7 day cultivation at 2$0^{circ}C$ was 12.3%.