In this communication, optimization of heat exchanger networks is studied using a new approach based on evolutionary algorithms. Heat exchanger networks with known structures are optimized using a new algorithm of swarm intelligence, namely, Cat Swarm Optimization (CSO). CSO is simulated by observing the behaviors of cats. Some cases from the literature have been solved with the proposed method, and results yield heat exchanger networks with lower costs than those ones presented in the literature for the studied cases. It is expected that the present study provides better understanding of design and optimization of the heat exchanger networks.