Abstract. The estimates of variability of allozyme loci in the members of a range of parasitic systems of West Siberia are obtained by the method of gel electrophoresis. The average level of variability of parasitic organisms (helminths, insects, crustaceans) is similar to that of non-parasitic invertebrate animals. Polyhostal parasites and parasites with complex life cycles have a higher level of variability than oligohostal parasites and parasites with simple life cycles.