The diet spectra of 8 spp„ belonging to several systematic and ecological groups, were analyzed by a serological method. It is demonstrated that the zygopterans possess rather uniform diets, consisting predominantly of chironomids. In contrast, the anisopterans have a more heterogeneous diet, which changes during the season; they forage on chironomids, mosquitoes, butterflies and horseflies, as well as on representatives of their own order. The food preferences of these odonates are connected with the peculiarities of the behaviour of the prey rather than its size. Thus, under conditions in West Siberia, they have a maximal effect on population sizes of chironomids and representatives of their own order.