In this paper a novel discrete Particle Swarm Optimization (PSO) algorithm is proposed to solve the Orienteering Problem (OP). Discrete evolution is achieved by re-defining all operators and operands used in PSO. To obtain better results, Strengthened-PSO which improves both exploration and exploitation during the search process is employed for experimental evaluation. Our proposed algorithm either achieves or improves the best known solutions compared to previous heuristics for the OP.