The paper, based on 15 prosobranch species inhabiting freshwater habitats in Poland, is devoted to a comparative analysis of the usefulness of several taxonomical characters. Such commonly used characters as: shell “macrocharacters”, operculum, soft part external morphology and pigmentation, ctenidium and osphradium, male and female reproductive organs and penis have already been described in detail in earlier papers of the author: in this paper they are essentially characterized and illustrated for comparative purposes. The paper presents descriptions of SEM structures of the radula, protoconch habitus and outer surface, teleoconch outer and inner surfaces and teleoconch inner structure visible on sections parallel and perpendicular to the growth lines of the shell, for all the 15 species. The descriptions are illustrated with 336 SEM micrographs. Then, all the characters are discussed considering their taxonomical usefulness. It is pointed out that all the characters show a more or less restricted usefulness. On the other hand, the SEM shell structural characters prove not less useful in taxonomy than “good” conventionally used ones. In Appendix II the author has described concisely the general organization of the shell of the studied prosobranchs.