The process of thinned antenna array synthesis involves the simultaneous minimization of a number of mutually conflicting parameters, such as peak sidelobe level and first null beam width. This necessitates the development of a multi objective optimization approach which will provide the best compromised solution based on the application at hand. In this paper multi-objective optimization is achieved using multi-objective binary cat swarm optimization (MOBCSO). A Pareto-optimal front containing all the probable designs is obtained in this process. Targeted solutions may be chosen from the Pareto front to satisfy the different requirements demonstrating the superiority of the proposed approach over multi objective binary particle swarm optimization method (MOBPSO).