|Remanufacturing has become an ever more important topic due to a growing need for environmental-friendly production strategies and an efficient use of resources. Traditional materials requirements planning (MRP) methods need to be adjusted in line with these new manufacturing environments where both manufacturing and remanufacturing are involved. In this study, a mathematical programming model is formulated for materials requirements planning decision in a multi-product, multi-period remanufacturing system where the assembly of final product is done both through use of parts procured from the disassembly of returned (used) (core) products and by ordering new (unused) parts. The decisions regarding the purchase and disassembly of new parts or used products as part of materials requirements planning are made for the purpose of minimizing the costs. The developed model takes into account, in a deterministic manner, the quality of the product to be disassembled, disposal cost of defective cores, lead time for purchasing new parts, disassembly bill of materials, disassembly capacity and disassembly time of each part. The mathematical model is illustrated through application to a sample problem, and an experimental design is provided in order to identify the ways in which different conditions in a manufacturing environment affect the total cost of the system.