Objective:To determine the faunal diversity of Muscidae and Fanniidae flies in Tehran,Iran. Methods:A net-capturing by direct observing method and fly trap were used to capture adult flies.To determine the fauna of flies in different habitats,4 biotopes including corpse(human, birds,livestock),garbage and decaying organic matters,animal carcasses and human indoor habitat were selected.Big hashing nets(95 cm in diameter) have been used for adult flies capture in these biotopes.Results:In this study,totally 2 418 adult flies from 8 families including Muscidae,Fanniidae,Calliphoridae,Sarcophagidae,Tachinidae,Syrphidae,Anthomyiidae and Conopidae were captured.Among these,1 279 belong to Muscidae and Fanniidae families. Four genera and 5 medically important species captured from two above mentioned families. Conclusions:Based on scientific documentation,2 species of Mvscina stobulons(M.stabulans) and Fannia scalaris(F.scalaris) are reported for the first time in Iran.However M.stabulans is a cosmopolitan species and its presence in Iran was probable. Objective: To determine the faunal diversity of Muscidae and Fanniidae flies in Tehran, Iran. Methods: A net-capturing by direct observing method and fly trap were used to capture adult flies. To determine the fauna of flies in different habitats, 4 biotopes including corpse (human, birds, livestock), garbage and decaying organic matters, animal carcasses and human indoor habitat were selected. Big has nets (95 cm in diameter) have been used for adult flies capture in these biopsies. Results: In this study, totally 2 418 adult flies from 8 families including Muscidae, Fanniidae, Calliphoridae, Sarcophagidae, Tachinidae, Syrphidae, Anthomyiidae and Conopidae were captured. Among these, 1 279 belong to Muscidae and Fanniidae families. Four genera and 5 medically important species captured from above mentioned families. Conclusions: Based on scientific documentation, 2 species of Mscscina stobulons (M. stabulans) and Fannia scalaris (F.scalaris) are reported for the first time in Iran. Host M. stabulans is a cosmopolitan species and its presence in Iran was probable.