In this paper, a hybrid ACO/ PSO heuristic to solve single row layout problem is proposed. As opposed to previous researches, the clearances and size of machines are treated as variables by using non-linear 0-1 mathematical model adopted from literature. ACO is used as constructive heuristic with a new pheromone update developed to achieve better performance on proposed algorithm. PSO, on the other hand, is used as an improvement heuristic to guide the ants to reach the best solution. To further improve the quality of the solutions, 2-Opt local search is added. The proposed hybrid ACO/PSO heuristic is evaluated with various sets of problems available in the literature, and the results are compared with those reported in the literature. ©2008 IEEE.