As the modern buildings have been gotten taller and narrower than before, the structural engineers have to perform both static and dynamic analysis for seismic loads that may affect on structures in order to make sure of the safety verifications and the optimal design requirements. The two common methods that always used for structural analysis against lateral loads are equivalent static method and response spectrum analysis. However, some different limits and restrictions for using the first method are stated by the universal design codes. This research studies the differences between the two methods through the results of seismic analysis by using Egyptian code of practice 2012, European Code 8: 2004 and Uniform Building Code 1997. It has been concluded that the equivalent static analysis method always gives higher results for drifts and overturning moments than those of response spectrum analysis method in case of using the aforementioned three design codes