This study investigated the effects of processing conditions on the shrinkage and warpage behavior of a box-shaped, polypropylene part created using a special microcellular co-injection molding process. Results were compared to the shrinkage and warpage of conventional and microcellular injection molded parts. A preliminary study was performed to determine processing condition limits and the steady state conditions for each combination of molding parameters. A 2(6-1) fractional factorial design of experiments (DOE) was performed utilizing the previously determined processing conditions. The molded parts were measured using an optical coordinate measuring machine (OCMM), which had previously been examined with a repeatability and reproducibility (R & R) study. These measurements were analyzed to determine the processing parameters that had the greatest effect on the shrinkage and warpage (S&W). The results of this analysis indicated that the supercritical fluid content and core-to-skin volume ratio had the greatest effect on the shrinkage and warpage of microcellular co-injection molded parts. The results of the experiment were that a considerable reduction in shrinkage and warpage could be achieved by utilizing microcellular co-injection molding.