MRP is a system intended for the batch manufacturing of discrete parts including assemblies and subassemblies that should be stocked to support future manufacturing needs.  Due to the useful information provided by MRP it has evolved into a Manufacturing Resources Planning, MRP II, a system that ties the basic MRP system to the other functional areas of the company such as marketing, finance, purchasing, etc.  The objective of this research, which was conducted at the State Company for Batteries Manufacturing, is to test the performance of some popular lot-sizing techniques used within MRP II framework. It is hypothesized that the technique which minimizes the total inventory costs does not necessarily minimize the need for resources such as machine capacity and labor force. To achieve this objective a computerized MRP II system was developed and simulated using random master production schedules of the 60A battery.  The results of the simulation runs confirmed the hypothesis.  This research recommends the use of the computerized MRP II system, developed here, in planning the manufacturing resources at the domain of research.