Increasing heights of multi-storeyed buildings, a better understanding of the wind, blast and seismic forces as well as the need for achieving maximum possible economy coupled with stringent safety requirements is leading to a greater, attention to the dynamic behaviour of buildings. The behaviour of plane frames with shear walls under dynamic loads has been investigated in detail (1, 2). It is possible to predict their mode shapes and frequencies with reasonable accuracy. An actual building, however, is a three dimensional structure consisting of rigid floors supported by vertical members. These floors behave like rigid bodies under lateral loads i.e., they have practically no inplane deformations, but rotate as rigid bodies influencing the stress distribution in the vertical members significantly. A method for the static analysis of multi-storeyed buildings with rigid floors under lateral loads has been reported by the authors elsewhere (3). The present paper extends this analysis to the dynamic behaviour of such buildings. An experimental investigation has also been carried out to determine the reliability of the theoretical approach.