Twenty-three Trichinella isolates have been examined by the isoenzyme typing of ten enzyme systems (LDH, ME, 6PGDH, G6PDH, GOT, AK, PGM, ACON, MPI, GPI). Four different zymodemes were obtained. All the examined isolates have shown an electrophoretic behaviour like one or other of four reference strains. The isolates from Italy and Yugoslavia have an electrophoretic mobility like T. nelsoni reference strain. The isolates from France, Holland, Poland and U.S.A. have an electrophoretic mobility like T. spiralis reference strain. For T. nativa and T. pseudospiralis we have only the reference strains. These results support the validity of the taxonomy of Trichinella genus in four good species.