The glucoamylase of Cladosporium gossypiicola degraded native rice, corn and potato starch by 54, 41 and 6%, respectively. The optimum pH for raw starch hydrolysis was 4.5 while that for soluble starch was 5.0. The enzyme adsorbed irreversibly to native starch over a broad pH range. Scanning electron microscopy (SEM) indicated that attack of the raw starch resulted in many pin-holes on the surface of the granules and digestion of the interior of the granule. The limited attack of potato starch granules was accompanied by the formation of a groove along the centre of the granule.