Reinforced concrete is a major construction material for civil infrastructure in current society. Construction design has always preceded the development of structural design methodology. Dramatic collapse of buildings has been observed after each disastrous earthquake, resulting in loss of life. To prevent such a loss Base isolation is used which enables a building to survive potentially devastating seismic impact by providing flexibility into the connection between the building and the foundation. The mechanism of the base isolator increases the natural period of the overall structure, and decreases its acceleration response to earthquake/seismic motion. A reinforced concrete building with lead rubber bearing is used. The study analysis performed to check for the adequacy of the base isolation against earthquake damage when compared to the conventional earthquake resistant design. A building was analyzed using the equivalent lateral force method and response spectrum analysis as fixed base (FB) and as isolated base (IB) with lead rubber bearing. The analysis represents a case study for reinforced concrete to show the ultimate capacity of the selected bearing system, and to make a comparison for the difference between the isolated base and the fixed base buildings. Results show that the presence of the lead rubber bearing reduces significantly the displacement, moment and shear generated for the same mode and hence the reinforcement required is also lesser when compared to the traditional fixed based structure.