Seismic design of non-structural elements is receiving much engineering attention nowadays because of widespread damage and resulting significant economic losses observed in several recent earthquakes worldwide. Current seismic design code provisions for non-structural elements recommend either the equivalent static method, as the most simple one, which does not consider dynamic properties of supporting structure at all the dynamic methods, as the most sophisticated one, which neglects any interaction between structure and non-structural elements. In this study, design seismic force of non-structural elements are investigated and evaluated through data base of the instrumented buildings, elementary structural dynamics, linear and nonlinear dynamic analyses, and analysis of 2DOF system simulating structure and non-structural element in view of the limitation of the current code provisions.