It has been postulated that mucosa-related antigens are involved in the development of IgA nephropathy. The aim of this study was to elucidate whether food antigens have any relation to IgA nephropathy in Japan. Sera from 15 patients with IgA nephropathy and 15 healthy controls were examined using an enzyme linked immunosorbent assay (ELISA). IgG, IgA, and IgM antibody titers were measured against six food-derived antigens, i.e. rice, soy bean paste, soy sauce, egg yolk, egg white and gluten, all of which are frequently found in the ordinary Japanese diet. No significant differences between patients and controls were found. It was concluded that food antigens appear to have little, if any, relation to IgA nephropathy.