The physical and chemical properties of the fuel used in internal combustion engines affect fuel economy and emission characteristics. Various additives are added into diesel fuel in order to improve fuel quality, achieve better combustion and reduce exhaust emissions. Acting as catalyzers during combustion, additives expedite fuel instability reactions and establish positive effects on engine performance. In the present study organic based manganese additive was added into diesel fuel. Combustion, performance and exhaust emission characteristics of the manganese fuel additives were investigated. The tests were carried out in a single-cylinder diesel engine. Among the fuels supplemented with organic based manganese additive, the best results were obtained from 12 ppm mixture rate. In comparison with diesel fuel, the maximum power of the DOMn12 fuel increased by 12.48% while the specific fuel consumption was reduced by 8.17%. At fuel load while CO, THC and smoke emissions were determined to remain at the minimum levels in the fuel DOMn12, NOx emissions reached the maximum level. (C) 2015 Elsevier B.V. All rights reserved.