The cell walls of some members of the Entomophthorales were isolated and analyzed for their carbohydrate composition. Genera were found to differ qualitatively, while the species of Entomophthora differed only quantitatively. Among the differences, the glucose–mannose ratio emerged as the most useful taxonomic criterion. Differences in cell wall carbohydrate composition paralleled differences in lipid composition previously reported in species of Entomophthora. Because of the absence of chitosan, the Entomophthorales should not be grouped with the Mucorales on the basis of their cell wall carbohydrates, but should form a new group of chitin–glucan fungi.