Abstarct: Intensive research in restricting inelastic damage in torsionally unbalanced building have been done .But It is not clear what can be defined as a torsionally irregular building? In this study, the torsional irregularities criteria as suggested by 54 countries seismic codes are compared with each other. Generally, seismic codes consider either in plan eccentricity or/and story drift for assessing torsionally irregularity. But seismic codes differ from each other in two aspects: 1) Definition of the above parameters (i.e. plan eccentricity and story drift) 2) The numerical limits of the above parameters where a building can be considered torsionally balanced system. In order to compare various code provisions, we classified one 8 stories and one 10 stories building either as regular or irregular according to different codes. The results were in contradiction to each other, i.e. while the building was regular according to some codes, it was irregular due to others. These contradictory results are mainly due to non uniform definition for an unbalanced system. The complexity involved in determining parameters such as location of center of rigidity can be another reason for contradiction results. Hence, it seems that more research is needed to reach generally accepted criteria for defining a torsionally unbalanced system. The use of energy-baxsed method to derive seismic design forces is discussed in this paper. TheEnergy balance concept and other equations to prevent the formation of undesirable mechanisms to be likely formed in the structure are used in deriving seismic design forces. The aim of this method is to study the ability of predicting structure’s behavior in the ultimate level and using of the maximum structure capacity to dissipate seismic input energy. For comparison between response of structures designed with equivalent static method and energy-baxsed method, two frxames with 10 and 15 story are designed considering above two methods. For which the results from nonlinear analyses of the frxames are compared. The results indicate that the designed by energy-baxsed method as compared with equivalent static method to cause an improvement in structure’s behavior.