Incorporating human workforce into flexible manufacturing systems is essential for maintaining companies’ competitiveness. Fully automated systems restrict flexibility, whereas the workforce could be considered to improve it : humans can learn, understand, and adapt. This paper studies a flexible manufacturing system that incorporates human operators and considers two variants of a problem : independent resources (two operators assigned to separate stations requiring workforce) and shared resources (one operator assigned to both stations). The objective is to evaluate their impact on system performance, including workforce-related indicators. A deterministic approach based on mathematical models is proposed for small and mid-sized instances, while a simulated annealing algorithm is used for larger instances. Initial solutions for the latter are generated using the NEH heuristic. The computational results show that independent resources lead to unbalanced workloads, whereas shared resources increase the makespan by 12.91% in average.