[en] A comparative study of a simplified radioimmunoassay (RIA) technique with the indirect haemagglutination (IHA) test in the diagnosis of 72 patients with hydatid disease indicated the greater sensitivity of the former. Both methods had an equal specificity in 60 control patients. RIA will serve as a useful addition to tests already available in hydatid serology. A comparison of the (RIA) technique with the fluorescent antibody test (FAT) in the diagnosis of 33 patients with early, active trichinosis and 30 healthy controls indicated an equal sensitivity and specificity of both methods. The adoption of RIA as an easier method is recommended. This study of a simplified radioimmunoassay technique for the diagnosis of hydatid disease and trichinosis in man is presented in two sections. (author)