In today's competitive business environment, the success of natural gas transmission, distribution, and gathering companies is tied to the value of its physical assets. In many cases, a company's long term competitiveness and profitability hinges on the reliability, efficiency, and environmental compliance of its gas machinery. Over the past few years, CNG Transmission Corporation has developed and implemented a comprehensive Engine Optimization Program. This program has resulted in significant reductions in fuel consumption, reduced maintenance costs (including time and material), and higher assurances of exhaust emissions compliance. The overall approach of the program is based on basic engineering and experimentation fundamentals. This paper will provide a general overview of the program and its components as well as a discussion of specific results and test data.