Attempts to localize cellulose, beta-(1,3)-glucans and chitin in Helicosporidia using EM cytochemical methods produced negative results and suggest that these carbohydrates are not present in the helicosporidial cell walls or pellicles. Cellulose was localized with cellulase-linked colloidal gold labeling technique, beta-(1,3)-glucans with immunocytochemical method, and chitin with lectin-gold cytochemistry. The labeling was done on vegetative stages as well as on cysts of Helicosporidia. Positive controls included Achlya bisexualis (cellulose, beta-(1,3)-glucans, chitin), Beauveria bassiana (beta-(1,3)-glucans , chitin) and several species of microsporidia (chitin). All positive controls yielded good labeling of the cell walls.