Prospero cudidaghense Firat & Yildirim (Asparagaceae) is described as a species new to science based on morphological studies. It is endemic to the eastern Anatolian region of Turkey. P. cudidaghense is known from a single locality on Cudi Mountain, located in Sirnak Province. It is an isolated taxon of the genus Prospero. It is related to P. autumnale and P. seisumsianum. Diagnostic morphological characters are discussed and compared with those of related taxa. It can be easily distinguished from all taxa in the genus Prospero by its spring flowering time, synanthous leaves, and chasmophytic habit.