We studied 60 species of helminths from 29 genera, 17 families, 8 orders, 3 classes, and 2 phyla parasitize horses in various regions of Karakalpakstan. Horses have been shown to be hosts to 53 species of Nematoda, 5 species of Cestoda and 2 species of Trematoda. The prevalence of helminths ranges from 0.7% to 33.6% and the intensity of infection from 1 to 12,538 individuals. The article reveals the biocoenotic relationships between ungulates and their helminths established by trophic links and proves the character of formation of helminthofauna in ungulates under the influence of natural and anthropogenic factors in the Aral Sea region. Additionally, the seasonal and age dynamics of horse infection with parascaridosis and setariasis in Karakalpakstan is determined.