Four different commercial systems were compared to identify 110 medically important yeast-like fungi found out in as many pathologic materials in three Medical Centers. The systems were: a) API 20C Aux (Ayerst), which represented the reference method in conjunction with the germ-tube test, aggregates 19 carbohydrate substrates for assimilation reactions; b) Uni-Yeast Tek (Flow) and Mycotube (Roche) were used to indicate assimilation and fermentation of 7 carbohydrate substrates and to determine other biochemical tests; c) Candida-Check (Poli) was based on agglutination reaction by specific antisera. Comparative testing of the methods provided correct identifications for 99.1% by API 20C Aux, 95.4% by Candida-Check, 89.1% by Mycotube, 88.2% by Uni-Yeast Tek. The good concordance of the methods and their optimal manuality, rapidity, and economy suggest a wider diffusion in microbiological laboratories.