Based on the analysis of collected herbarium specimens during expeditions conducted between 2004 and 2018 as well as data published by others, it has been revealed that at present the genus Crataegus is represented by 22 species in the flora of Nakhchivan. Out of these, 17 are wild species distributed in the wild. Crataegus chlorocarpa, C. ferganensis, C. sanguinea, C. songarica, and C. turkestanica have been introduced into the cultural practices by their use in the landscaping of parks and gardens. In order to clarify the current state of the genus Crataegus in the flora of the Nakhchivan, a comparative analysis of herbarium collections was undertaken on the specimens deposited at the herbarium of the Institute of Botany of Azerbaijan National Academy of Sciences, Institute of Bioresources of the studies conducted have taken into account the rare and endangered species of C. orientalis and C. pontica. These have been included in the Red Book of Nakhchivan Autonomous Republic and the ways for their protection elaborated. This chapter covers data on the synonymous species and their patterns of distribution among high-altitude zones, habitats, and flowering time and fruit formation.