<p>We tend to see many multiple storey developments in most of the cities, the reason being the development of urban centers that in turn has led to immigration of huge population. Such buildings are designed to sustain the action of dead and live loads. Hence, designing such structures is not a tedious task. In general practice the masonry infill in multi-storey building is having influence on strength and stiffness of framed structures. Lateral forces that are present during earthquake are influenced by many structural parameters, amongst which is the fundamental natural period of vibration. This is known as base shear. Hence, the bending moment and shear forces in RC elements, the internal stresses in MI, storey drifts and many more are influenced by the shear values, both base and storey, that are calculated using fundamental natural period of vibration. It is thus important to evaluate the fundamental period of vibration of MI-RC frames to ensure a better understanding of behaviour of these frames under lateral loads. Under lateral loads, the MI separates from frame because of poor interfacial behaviour. This paper aims at the evaluation of the fundamental period of vibration of MI-RC frames by modelling the frames in different ways which includes geo-fabric interfacial strengthening between MI and RC particularly in the Indian context wherein the strength and elastic modulus of MI are relatively low.</p>