Often the biggest log jam in the development of new medical devices is the successful manufacture of its plastic components. Despite the significant advantage of injection molded plastic parts, the complex interaction of plastic materials, part design, mold design and process creates endless challenges that confound even the latest state-of-the-art FEA and CAE process simulation programs. These challenges are compounded as we increasingly move toward miniaturization and the molding of micro-features in medical parts. This paper presents an overview of some of the more critical issues relating part design and manufacturability. The presentation simplifies some of the more complex interactions and provides guidelines as to how to minimize the risks they cause.