Multi-threshold CMOS is an increasingly popular circuit approach that enables high performance and low power operation. In this paper Reverse Body Bias (RBB) with high-Vth is used to reduce the leakage power in nanometer technology for the proposed array multiplier with CSA design. The results are carried out by H-Spice for 90nm and 65nm BSIM model files. MTCMOS circuits have shown good results than the conventional circuits. © 2012 Springer-Verlag.