The paper discusses the distribution of Nikolsky’s pitviper, Gloydius caucasicus, in Azerbaijan. According to the authors’ own research results, literature data and museum collections, 32 findings of this species in the Jalilabad (1 locality), Yardymly (11 localities), Lerik (10 localities), Lenkoran (10 localities) and Astara (5 localities) administrative districts are presented. All the known findings of the pitviper are located within 10–1,980 m above sea level in the Lenkoran lowland, the mountain forest belt of the Talysh Mountains, as well as in the mountain-xerophytic steppe of the Yardymly, Deman and Diabar intermountain depressions. The species is recorded on the territory of “Hirkan” National Park and Zuvand regional reserve. G. caucasicus is a rare snake species in Azerbaijan. The main threat to the pitviper in the region is habitat loss. To preserve the species in the northwestern periphery of the habitat, the authors recommend creating a specially protected natural area in the Jalilabad and Yardymly districts on the Alashar-Burovar Ridge. It is also necessary to include G. caucasicus into the Red Data Book of the Republic of Azerbaijan in the category “Vulnerable species” (VU).