A strategy for testing naval diesel engines for exhaust emissions was developed. A summary of existing legislative and resulting regulatory initiatives pertaining to marine diesel engine emissions was prepared. Naval ship data covering 11,500 hours of engine operation for four U.S. Navy LSD 41 Class amphibious ships was analyzed to develop a class operating profile. A procedure was detailed combining ship hull form characteristics, ship propulsion parameters, and ship operating profile to derive an 11-Mode Duty Cycle for testing LSD 41 Class propulsion diesel engines. The application of civilian industry standard duty cycles to predict naval ship propulsion engines was found to be inadequate by comparison of the derived 11-Mode Duty Cycle with seven existing cycles.