Improvement of fuel properties is essential for the suppression of diesel pollutant emissions along with the optimization of combustion-related design factors and exhaust after-treatment equipment. Studies conducted in the past have shown that a significant reduction of pollutants using oxygenates as alcohols, ethers, glycol ethers, methylals and carbonates. The present paper experimentally investigates the influence of oxygenated diesel fuels on the emissions with the use of two different synthetic oxygenated compounds namely Diphenyl ether (DPE) and Diethelene glycol dimethyl ether (DIGLYME). Several diesel fuel blends, which contain 10% and 15% by volume of DPE and DIGLYME, were prepared and the effect of these blends on emission characteristics were studied on a twin cylinder direct injection diesel engine. The blends were tested under the different load conditions and the results shows, there is significant reduction of engine emissions of hydrocarbon and carbon mono oxide emissions while the coefficient of light absorption of smoke opacimeter decreases by about 50% for DPE10, DIGLYME10 blend and it was reduced by about 60%for DPE15 and DIGLYME15 blend. © 2006-2011 Asian Research Publishing Network (ARPN).