For many years the use of in-mold fasteners has been avoided for various reasons including: not fully understand the load cases in the part, the fear for quality issues to occur, the need for servicing, or the lack of understanding the complexity of all failure modes. The most common solution has been the use of secondary operations to provide attachments, such as, screws, metal clips, heat staking, sonic welding or other methods which are ultimately a waste in the process and increase manufacturing costs. The purpose of this paper is to take the reader through a design process which allows for the design of in-molded attachment clips on plastic parts. The paper explores the design process for in-molded attachment clips starting with a design concept idea, testing the basic concept using a personal 3D printer, optimizing the design with physical tests and CAE analysis, and finally producing high resolution 3D prototypes for validation and tuning. The ultimate goal of this paper is to convey design lessons learned, be a guide for in-molded attachment clip design and provide a better understanding of the issues to be faced when taking on this challenge. We hope this encourages other engineers to design more efficient and robust parts by using the computational, prototyping and information resources available to the automotive engineer in today’s innovative environment.