Practically no studies are available on the presence of kinin-decomposing enzymes in yeasts. Different preparations (intact washed cell suspensions, cell-homogenised blastospores, nutrient media, supernatant of raw fungus suspensions) of Candida strains sampled from foci of disease and from the environment were studied qualitatively and quantitatively fro the presence of kinin-inactivating enzymes. The parameter measured is the time-dependent inactivation of bradykinin by the test strain preparations as determined in the isolated guinea-pig ileum by the water-bath test. Preceding surveys of the basic presence of kinin-decomposing enzyme activity in 10 Candida strains from foci of disease revealed that only undiluted, intact washed suspensions of spores were capable of bradykinin inactivation. Intact washed blastospores from 4 other strains sampled from foci of disease (Candida tropicalis B5, Candida tropicalis B12, Candida albicans C10, Candida albicans A23) diluted 1:10 by volume did not exhibit bradykinin decomposition at the concentration studied. In contrast to this, identical preparations of three strains from the environment (Candida tropicalis E2, Rhodotorula rubra H14, Saccharomyces lactis R15) were exhibiting kinin-inactivation of partially high intensity which was still enhanced by cell homogenisation. The Candida brumptii Q6 strain, however, did not induce kinin breakdown. In the case of Candida tropicalis E2, the enzymes could be demonstrated also in the nutrient diluted 1 : 2. Supernatants obtained by centrifugation of raw fungus suspensions were ineffective in respect of strains from foci of disease as well as such from the environment. Bradykinin was protected against inactivation by treatment of all kinin-decomposing preparations with 1,10 phenanthroline, acid and heat. Thus, the kinin-decomposing enzymes involved were kininases. In a general view, species-specific differences in the presence of kininases among Candida strains were recognizable.