This paper describes the methodology by which a combination die cast magnesium and extruded aluminum door frame was developed using a current production steel door design as the base model for comparison. Product performance data, such as side impact requirements and overall door stiffness, along with the packaging of existing internal hardware, is presented. The results are verified by computer modeling. A prototype casting was produced to validate and compare castability requirements and geometry constraints of the door frame.An economic study is included that investigates the potential of developing such a system suitable for production. The results suggest that economic benefits may be obtained by using such a lightweight door system compared to an existing steel door design.