An updated checklist of plant species increases knowledge about flora available for a given area and are fundamental to the public awareness and conservation of plant diversity. These kinds of achievements are closely linked to the implementation of Global Strategy for Plant Conservation Target 1. This paper provides a supplement for an updated nomenclatural checklist of the non-flowering vascular flora of Azerbaijan, one of the main plant diversity center in the Caucasus. Information on taxonomy and nomenclature of non-flowering vascular plants, an updated list of the accepted names and principal synonyms of the taxa of native and xenophyte plants known to occur in Azerbaijan are presented in the checklist. Their distribution and life form, rarity and endemic status are also quantitatively analyzed. It includes 115 species, 27 infraspecific taxa (subspecies and varieties) and 11 natural hybrids of native and naturalized non-flowering vascular plants of Azerbaijan belonging to 22 families and 50 genera. After the publication of the first volume of Flora of Azerbaijan about 50 new taxa were recorded as a result of studies by various researchers. The nomenclatural changes were done among 28 taxa according to recent phylogenetic and systematic investigations of relevant plant groups. An up to date nomenclatural checklist will be a key text to develop e-flora of Azerbaijan and is necessary for future systematics, ecology, physiology, ethnobotany and phytochemistry in Azerbaijan.