This paper presents the Clonal selection algorithmic approach to minimize power loss and energy cost by optimal capacitor placement and sizing in Radial Distribution System (RDS). The clonal selection optimization for optimal capacitor allocation is considering the daily load curve, which is represented by a given number of load levels. As an important branch of the Artificial Immune Systems (AIS), the Clonal Selection Algorithm (CSA) stems from the clonal selection mechanism that describes the basic natural immune response to the stimulation of non-self cells (antigens). To check the feasibility, the proposed method is applied on standard 33 and 69 bus radial distribution systems. Numerical results obtained from the given approach are compared with other methods. The proposed approach results seem to surpass the solution given by other methods. © 2006-2015 Asian Research Publishing Network (ARPN).