This paper concentrates on the results of sustainability caused by Courtyard as a climatic element in Iranian traditionalarchitecture of cold regions. Traditional architectureof Iran is perceived sustainable for having sustainablefeatures. It is able to response to environmental problems from a long period. Its features are based on climatic factors as well as local construction materials of cold regions and Courtyard (hayate- markazi) is one of this features .Courtyard as one of the determining and organizing factor of traditional architecture in cold regions involves varies aspects.