The Saccharomyces cerevisiae allergens were characterized by IgE-immunoblotting with serum samples of 83 patients; 63 represented patients with atopic dermatitis with previous positive skin prick test or RAST for S. cerevisiae, seven patients with AD but negative test results and 13 were non-atopic controls. Disrupted whole body extract of S. cerevisiae was used in the assays. From the patients tested 41 patients with atopic dermatitis appeared positive in IgE immunoblotting revealing 22 IgE stained bands. From these bands 10 represented intermediate allergens, and 12 minor allergens. The most frequent staining was obtained with the 48 kD band (39%). When the staining pattern of 45 kD and 48 kD bands and mannan was compared with Candida albicans allergens or purified baker's yeast enolase a simultaneous binding was seen with the 48 kD band of S. cerevisiae and the 46 kD band of C. albicans and enolase whereas the 45 kD band was neither associated with the 46 kD band of C. albicans nor purified enolase. High molecular weight staining was found in five samples. The staining pattern was associated with the mannose containing structures in parallel with C. albicans.