This paper investigates the software development and experimental evaluation of warpage in injected molded parts. Warpage is one of the primary defects in dimensional instability, which is not easily removed by changing processing parameters, and thus, in most cases imposes mold-rebuilding expenes. Hence, predicting the occurrence of this effect is necessary especially in multi-component parts in assembly. Due to the high cost of special softwares, an appropriate software development was found to be effective using commonly-used software packages. In this research, three important steps, namely solidification, shrinkage, and warpage were analyzed and experimentally verified. The results show that the developed software could predict the final shape and warpage in a reasonable degree. The effect of increasing pressure is to lower the warpage, as expected. When compared with the part without rib, the existence of rib was found to have a considerable effect on increasing warpage.