Northwestern Iran is one of the key regions in the archaeological researches, especially during the Iron Age. Tepe Hasanlu is an important ancient site due to its long-term occupation and extensive excavations, with relatively complete studies. This paper dealing with the results of recent archaeozoological researches of Hasanlu, to complete the lack of studies on the subsistence economy of the site. The studied faunal remains of Hasanlu derived from campaigns of 1970, 1972 and 1974, which are housed in the Osteology Department of the National Museum of Iran. This paper intends to examine the subsistence economy and animal exploitation patterns during the Iron Age in Tepe Hasanlu. The faunal remains of Middle and Late Bronze Age and Historic period also evaluated to better perception of changes and evolutions in subsistence strategies of Iron Age. The results of studies pointed to the developed animal husbandry during all periods of Hasanlu, which domesticated sheep and goats, and cattle were the most important exploited resources. Equids also allocated the considerable portion of the collection which especially bred in Iron Age. The same pattern identified in contemporaneous sites such as Haftavan Tepe and Dinkhah Tepe in northwestern Iran.