The development of ascospores and heat resistance was determined in McClary's acetate broth in the presence of two sporulation inhibitors, ethanol and erythromycin. The inhibitors delayed sporulation without preventing development of heat resistance. The presence of ethanol in growth media caused cells to have increased heat resistance. The fatty acid and chitin contents of sporulatingHansenula anomalacells were determined. Highest triglyceride content of cells was associated with the initiation of sporulation. This phenomenon was not observed for phospholipid. As the ratio of saturated to unsaturated fatty acids in triglycerides increased, so did the heat resistance. However, the chitin content of cells was not correlated with heat resistance.