L'etude des collections de Rhinopoma microphyllum a permis de prociser l'aire de repartition de cette chauve-souris en Iran et de rendre compte de nombreux nouveaux specimens provenant de nouvelles localit£s. Une sous-espece nouvelle, R. m. harrisoni a pu Stre d6crite du sud-ouest de l'Iran o eile se trouve sou vent proximito de R. m. microphyllum. Cette derniere a έΐέ collects des altitudes plus έΐβνέββ et dans des zones plus froides que R. m. harrisoni.The taxonomic status of the Greater Mouse-tailed bats (Rhinopoma microphyllum) of southern Iran is unclear at this time (Kock 1969, andGaisler 1970). Harrison (1964) and Kock (1969) referred specimens from northern Egypt and the Levant to Rhinopoma microphyllum microphyllum as did Gaisler (1970) for specimens from Afghanistan and Pakistan. Gaisler (1970) referred specimens from Misham [= Mishen], Telespid and Las Bela, Iran, to the nominate subspecies. Kock (1969) placed a question mark on his map at the head of the Persian Gulf, the area from which the Mishen and Telespid specimens were captured, and indicated by a dot his belief that the specimen from Ahmad Mahmoudi (Lay 1967) is JR. m. microphyllum. However, Kock has not examined this latter specimen and measurements of it have never been published.Our study of collections of Rhinopoma microphyllum, made under the auspices of a mammal survey of Iran by the Smithsonian Institution and the 1968 W. S. and J. K. Street Expedition to Iran cosponsored by Field Museum of Natural History and the Iran Department of Game and Fish, has revealed the presence of an undescribed subspecies of R. microphyllum in southern Iran. This discovery, together with a review of previously collected specimens, has clarified the taxonomy of this species in Iran.