The purpose of the research is to study mixed infections of gastrointestinal strongylates and Anoplocephala sp. in sheep in the context of the vertical zonality of Dagestan.Materials and methods. In 2000-2020, 360 collections of the digestive tract of sheep and 600 fecal samples were studied in the plain, foothill, and mountain belts of Dagestan. The material was analyzed in young animals up to 1 year old, animals from 1 year to 2 years old, and animals over three years old. The study was performed in all four seasons. The work used methods of full helminthological dissection according to K. I. Skrjabin, sequential washing of feces with a saturated ammonium nitrate solution according to G. A. Kotelnikov, V. M. Khrenov and Berman-Orlov, as well as larvae cultivation in a thermostat.Results and discussion. Mixed helminth infections were recorded in sheep in all natural and climatic zones of Dagestan. The greatest species diversity, high rates of infection prevalence (IP 15.0–43.3%) and infection intensity (II 16–3860 sp.) were observed at gastrointestinal Strongylata and Anoplocephalata infections in the plain belt. Of the pathogens in the plain and foothill belts, mixed infections were dominated by Chabertia, Bunostoma, Trichostrongylidae, Haemonchus, and Nematodirus; and from Anoplocephala – moniezia. The IP and II rates were significantly lower, 25–8.3% and 43–32 sp., respectively, in the mountain belt at an altitude of over 2500 m above the sea level. Lambs in the first year of age were infected with Chabertia, Bunostoma (B. trigonocephalum), Trichostrongylidae (T. axei and T. vitrinus), Haemonchus and Nematodirus (N. spathiger) in the plain and foothill belts. In the second year of age, sheep older than three years were infected with T. axei, T. capricola, T. vitrinus, T. colubriformis, O. ostertagi, O. circumcincta, O. occidentalis, O. antipini, O. leptospicularis, C. punctata, C. oncophora, N. filicollis and N. abnormalis with IP of 2.5–8.3% and II of 1–11 sp., in addition to the dominant species. We recorded M. expansa, M. benedeni, T. giardia and A. centripunctata (IP 2.5–30.0%, and II 1–48 sp.). In the mountain belt over 2500 m above the sea level, lambs were infected with Ch. ovina, B. trigonocephalum, T. axei, H. contortus, N. spathiger (IP 8.3–11.6%, II 3–32 sp.) and M. expansa (IP 2.5–5.0%, II 1–29 sp.). Young animals in the second year of age and sheep over three years old had mixed infections with the species as indicated in lambs (IP 3.5–8.3%, II 3–29 sp.).
