The AutoMicrobic system (AMS) Yeast Biochemical Card (Vitek Systems Inc., Hazelwood, Mo.) is a system which has been designed for rapid and automated reporting of yeast identification in the clinical laboratory. Recent improvements have been implemented in the AMS data base to expand and enhance its yeast identification capabilities. These improvements include the addition of seven biotypes, changes in data analysis scheme, and construction of the taxonomic keys. The updated system was compared with the API 20C (Analytab Products, Plainview, N.Y.) yeast identification system and a rapid conventional method, using 1,106 clinical and stock yeast isolates. With these improvements, the AMS Yeast Biochemical Card had a correlation of 98.8% with the API 20C system and 93.4% with the rapid conventional method and significantly increased its capability of identifying Cryptococcus neoformans (98%). The most difficult organisms for the system to identify in 22 to 24 h were Cryptococcus terreus (58%) and Cryptococcus uniguttulatus (73%). The updated AMS not only provided more rapid results which were comparable to the other two systems but gave a substantial savings in set-up and reporting time as well.