Tests to detect circulating antibodies to Candida albicans antigens were performed in sera from 27 immunocompetent patients, 15 of whom had deep-seated candidiasis and 12 of whom were colonised by Candida albicans. For the diagnosis of deep-seated candidiasis in patients with either deep-seated candidiasis or Candida albicans colonisation, counterimmunoelectrophoresis had a sensitivity of 87% and a specificity of 75%. Using immunoblotting it could be shown that antibodies to 35K, 47K, 68K and 88K antigens of Candida albicans occurred more frequently in patients with deep-seated candidiasis than in colonised patients. The presence of dense bands in immunoblots representing antibodies against the 47K and/or 68K antigen served to discriminate significantly between deep-seated and superficial candidiasis (p less than 0.05).