The purpose of this study is to improve the diagnosis of peanut allergy. In order to standardize test substances for in vivo and in vitro diagnostic, the type I allergy-associated single components of peanuts have been identified and characterized with the aid of patients' sera and monoclonal antibodies. For allergen detection IEF-immunoprint-, SDS-PAGE-immunoblot- and 2-D electrophoresis-techniques have been used. A comparison of control sera and patients' sera showed that both contained peanut specific IgG-, IgA- and IgM-antibodies. In contrast, peanut-specific IgE-antibodies were only detectable with patients' sera. In IEF-immunoprint the most intensive IgE-bindings showed up in pl-range from pH 5.5 to 7.5. In SDS-PAGE-immunoblot major allergens could be identified at molecular weight ranges of 17, 30, 48 to 66 and 116 kD.