Traditionally, injection mold design has been quite empirical, relying on previous experiences, rather than sound engineering principles. This is due to the lack of algorithms available to injection mold designers. With the continuous advancement of the CAD/CAM technology, new principles can be developed to generate fully integrated and automated mold design procedures. This paper presents a methodology of a more analytical approach to mold design. Such methodology is based on the branching technique which is utilized to develop the required data for the rheological analysis. A post-processor is also developed to enable mold designers make their decisions. Numerical experiments are included to demonstrate the scope of the analytical approach.