The paper gives results of a project to design, develop, and demonstrate a diesel engine nitrogen oxide (NO-x) and particulate matter (PM) control package that will meet the U.S. Navy's emission control requirements. (NOTE: In 1994, EPA issued a Notice for Proposed Rule Making (NPRM) addressing emissions from marine engines, including diesel engines. The proposed standards for diesel engines include: 9.2 g/kWh for No-x, 11.4 g/kWh for carbon monoxide (CO), and 0.54 g/kWh for PM.) A combination of engine timing retard, external exhaust gas recirculation, and an oxidizer reduced NO-x and CO emissions to the level recommended by the proposed EPA standard, while PM emissions remained unchanged in a test engine for a wide range of operating conditions. A shipboard test showed similar reduction of No-x and CO without reducing fuel efficiency or the performance of the propulsion engine. This may represent one of the most cost effective methods to retrofit the Navy's diesel engines to meet future emission standards.