Structural design codes are calibrated using reliability-based calibration methods. However calibration of many codes is based on a single load combination (dead and live load combination) and a single load ratio called calibration point. Since, this assumptions disregard the impact of other load combination the reliability assessment of existing design codes is important. Therefore structural design codes need to be reformulated to achieve consistent levels of safety and to provide more rational rules for desired performance level. The object of this study is to the assessment the reliability level of flexural beams in Iranian Structural Steel code for a sample region (greater Tehran) by considering different load ratios and all of load combinations. Here for earthquake and wind load which is site dependent, local statistical data are provided. For other random variables the benchmark studies have been used.