This paper considers the part assignment to workstations in flexible manufactuirng system (FMS). Parts are processed through several workstations according to processing order. The machines of each workstation can do multiple Processing functions. Therefore, a processing of a part can be processed in several workstations, which are non-identical in functional performance. Although a processing of a part can be processed in the multiple workstations, it has to be processed in only one among available several workstations, Parts are transported with unit load by automated guided vehicles (AGVs). The criteria of part assignment is to minimize the maximum value of the processing times of each workstation and the total transport times of vehicles. Model formulation is suggested, and numerical example is shown.