An earthquake is a natural phenomenon associated with the violent shaking of the ground which cause damages to the buildings due to the presence of structural irregularities. These irregularities are unavoidable but its behaviour can be studied for the analysis of seismic response of structures. In this study, both horizontal irregularities and vertical irregularities are considered. Reinforced concrete frame buildings with masonry infill walls have been widely constructed for commercial, industrial and multi-family residential uses in seismic-prone regions worldwide. The masonry walls has a significant impact on the seismic response of an Reinforced Concrete frame building, increasing structural strength and stiffness and also results in brittle failure mechanisms. The objective of this study is to understand the importance of irregularities, behavior of different irregularity of reinforced concrete structure to seismic forces, its failure pattern during earthquake, to suggest safe performance level for various types of irregularities and to study the short column and long column behavior to earthquake.