Synchronous, parallel discrete event simulation (PDES) is the simplest and lightweight approach to speedup large-scale simulations by scheduling as many events, of the same simulation cycle, to be executed concurrently. The scheduling technique to achieve perfect load balance and scalability is a key challenge for an efficient synchronous PDES. In this paper, we proposed a technique for balancing loads to fit the number of available processors on multicores. The technique has been implemented on a synchronous PDES tool called P-HASE (the Parallel - Hierarchical computer Architecture design and Simulation Environment) using the NET 4.0 concurrency runtime and OpenMP. Eight simulation models have been evaluated on 4-, 8-, and 16- core machines. The results show that the models using P-HASEare faster than HASE for 18 - 6.5 times; and maintain their performance when changing the numbers of processors. The results confirm that the simulation models created by using the P-HASE tool are highly scalable for multicore architecture. © 2012 Springer-Verlag.