A total of 98 marine mammal records from Iranian coastal waters of the Persian Gulf and Gulf of Oman were compiled of which 66 are previously unpublished new records. Seventy-nine were from the Persian Gulf and 16 from the Gulf of Oman coast. The largest numbers of records were from Qeshm Island and Bushehr Provinces. Records of finless porpoise (Neophocaena phocaenoides), Indo-pacific humpback dolphin (Sousa chinensis) and Indo-pacific bottlenose dolphin (Tursiops aduncus) were by far the most numerous probably reflecting their inshore distribution and local abundance. Other species recorded are common dolphin (Delphinus capensis tropicalis), rough-toothed dolphin (Steno bredanensis), Risso’s dolphin (Grampus griseus), false killer whale (Pseudorca crassidens), and dugong (Dugong dugon). Evidence of 22 Mysticetes were obtained eight of which were tentatively identified as Bryde’s whales (Balaenoptera edeni), three as fin whales (Balaenoptera physalus) and three as Humpback whales (Megaptera novaeangliae). The largest threat to marine mammals in Iran is likely to be incidental capture in fishing gear. Six by caught finless porpoises were recorded and this species may be particularly vulnerable to incidental mortality in gillnets. Recommended marine mammal research, conservation and management small projects in Iran are described.