Abstract: This work proposes a new approach for the optimal sitting and sizing of capacitors in Radial Distribution Systems (RDS) with the objective of mitigation losses of the system subject to the constraints. In the present approach new combined approach of Voltage Stability Index (VSI) and Bat Algorithm (BA) are applied to decide the optimum placement of capacitors. BA is utilized to determine the optimum size of capacitors. The present approach is implemented to the IEEE 85 RDS. The simulated results validate the show and efficiency of the present approach capably.