SUMMARYThe ability ofTalaromyces emersoniito synthesize extracellular cellulase has been studied in stationary liquid medium. While this organism could not degrade filter paper, its cell-free filtrate hydrolyzed soluble carboxymethyl cellulose to reducing sugars. Hence it was suggested thatT. emersoniiwas able to synthesize the Cx, but not the C1enzyme. The optimum temperature for synthesis of the Cxenzyme was found to be 45 C, while that for its activity was 50 C. The bestpH for the enzyme activity was 6, and enzyme production was found to be affected by the concentration of cellulose in the medium. The probable participation ofT. emersoniiin the degradation of insoluble cellulose in the natural habitat and in the biodeterioration of stored agricultural products is discussed.