Attempts were made to prepare a sensitive antigen from C. albicans suitable for detecting humoral antibodies and hypersensitivity in deep-seated candidiasis, in patients at risk of invasive candidiasis and in allergic states caused by Candida. 5343 persons suffering from systemic, bronchial, vaginal candidiasis, bronchial asthma, chronic bronchitis, polyarthritis nodosa, ulcus cruris, malignancy, rhinitis pollinosa, vasomotorica, and non infected miners, farmers and blood donors were investigated on the presence of antibodies and hypersensitivity against 8 different antigen preparations. The extracellular protein and mannan- protein isolated from the cultivation medium of C. albicans proved the most sensitive for specific anticandida antibodies. The mannan, especially the mannan isolated from the cell surface of C. albicans determined best for the allergy. Comparison made of commerical Candidine showed similar activity. The whole cell C. albicans antigens as well as the mixed Candida antigen reacted much weakly. Comparison made of autoantigen, C. albicans and mixed C. albicans antigen proved the highest sensitivity of the autoantigen.