213 oral isolates of Candida albicans and 62 isolates of C. tropicalis were tested for their hydrolytic enzyme profiles with the API ZYM system. One major biotype accounted for more than 50% of the isolates and a number of minor biotypes was recognized in both Candida species. The enzyme profiles of the major biotypes were identical and one quarter of the C. tropicalis isolates possessed a beta-glucosidase which has not been previously described.