N-acetylglucosamine, galactose, N-acetylgalactosamine and mannose and (or) glucose were present on specimens of two populations of Globodera rostochiensis and two of G. pallida representing four different pathotypes. Individuals within the pathotypes varied in the amounts of some of the saccharides present. The Pa[subl] population differed from the other populations in the presence on all individuals of N-acetylgalactosamine and the absence of extensive residues of mannose/glucose. TEM studies showed that N-acetylglucosamine and mannose/glucose were present on the exudate from the amphids of juveniles from the Ro[sub1] population. Key words: amphidial exudate, N-acetylglucosamine, galactose, N-acetylgalactosamine, mannose, glucose, fluorescence, microscopy, electron microscopy, rhodamine, ferritin, pathotypes, potato cyst nematode.