The examination of 90 patients with superficial and visceral candidiasis, as well as Candida carriers, has revealed that the heavy contamination of the body with fungi of the genus Candida is accompanied by the specific transformation of the immune system, manifested by differences in the character of sensitization to Candida antigens: in the patients with superficial and visceral candidiasis the B-system of immunity is sensitized to a greater degree, while in the Candida carriers the sensitization of the T-system is more pronounced. Despite the fact that the immune system of patients with the disseminated form of visceral candidiasis is capable of developing the delayed hypersensitivity (DH) reaction to bacterial allergens, such patients have been shown to develop DH to Candida antigens only in rare cases. This is probably due to disturbances in their immunocompetent systems, caused, seemingly, by the secondary immune insufficiency.