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Khorjini (saddle) frame is one of typical structural systems in Iran and needs seismic retrofit based on previous research reports. In this paper, a sort of hysteresis dampers called buckling restrained braces (BRB) is considered and its behavior and design procedure are investigated to study its effect on seismic performance of steel frames. Finally, a typical khorjini (saddle) frame has been seismically retrofitted and was analytically subjected to the time-histories of the Naghan, Tabas and Northridge earthquakes. Numerical results showed that BRBs have high capability in seismic design of new structures and seismic retrofit of existing structures as well.