This document presents the design of an expert system for diagnosing dilated cardiomyopathy. The system uses CLIPS (C Language Implementation Production System) as the development tool. It includes 46 rules and a decision tree to diagnose patients. Certainty factors are used to improve accuracy. The system was evaluated against physicians and received positive feedback. In conclusion, expert systems can help with medical diagnosis of conditions like dilated cardiomyopathy. Future work involves developing a fuzzy expert system for more accurate diagnosis.