A computer software has been developed to speed up the design process of automatic degating molds used for injection molding of plastic balls. Following an introduction to the ball making process and the associated mold design consideration, the algorithm and formulation of the software are presented. To demonstrate its versatility, the software developed is adopted to design both testing and production molds that best meet the design and production requirements. Two testing molds were built. While one was used to verify the gate size predicted, the other was built to confirm the workability of the automatic degating design. The results of testing runs have also been used to finalize the details for designing the production mold. The software developed is compact enough to be run on an IBM/PC compatible and has the capability to communicate with commercial CAD/CAM systems to provide necessary drawings or CNC files for mold fabrication.