Progressive collapse of the structure occur, when the major structural load carrying members is removed suddenly and the remaining structural element are not capable of supporting the weight of the building and eventually resulting in collapse and failure of the structure. The main purpose of this investigation is assessment the progressive collapse capacity of steel intermediate moment frame (IMF steel frame) that designed according to Iranian National Building Code (part 10). In this paper, using nonlinear static analysis (pushdown analysis) procedure the progressive collapse capacity of IMF steel frames with 3, 7 and 12 stories are evaluated under 6 different scenarios. Progressive collapse potential of MRF frames are evaluated based on the acceptance criteria of last edition of UFC 4-023-03 document. The studied steel frames are significantly vulnerable under progressive collapse scenarios. The obtained result showed the frames with high storeys are more vulnerable in comparison with than frames with low storeys under similar collapse scenarios.