Combined heat and power economic dispatch is an important optimization problem in a power system integrated with cogeneration units. In addition to the optimal solution satisfying the power balance equality constraint and the bounds of the thermal units, it must also lie within feasible operating region of the cogeneration units. This increases the complexity of the problem, and a potent meta-heuristic algorithm is required to solve the problem. This paper investigates the optimal solutions of the combined heat and power economic dispatch problem obtained by a recent meta-heuristic salp swarm algorithm. Transmission losses of the power system and valve point loading have been taken into consideration in this work. The algorithm is tested on standard test system available in literature. The results indicate there is scope for improvement of the salp swarm algorithm to solve combined heat and power economic dispatch problem. © 2021, Springer Nature Singapore Pte Ltd.