A sensitive solid-phase enzyme-immunoassay for the detection of rubella virus specific IgG and IgM antibodies has been developed. Wells of polystyrene trays were sensitized with purified rubella antigen. A substrate employed in enzyme-histochemistry, which gives a stable staining, was used to allow direct determination of titre values. One hundred and thirty-five human sera were tested. Antibodies titres, detected using this glucose oxidase immunoassay, correlated well with those obtained using a virus haemagglutination inhibition test. With this procedure sera can be tested without any pretreatment and evaluated within one day. Moreover, TIE is more sensitive and specific antibodies are detected earlier.