JP-8, which is an aviation fuel, was accepted as a common military fuel towards the end of 1980s by NATO countries. JP-8 containig 99.8% kerosene is blended with various additives to make it suitable for military applications. The most important feature having a freezing point of below -40 degrees C. The purpose of this study is to investigate the possibility of using JP-8 and referance diesel fuel blends. In this study JP-8 was added to diesel fuel with volumetric ratios of % 5, % 10, % 25 ve % 50. Experiments were carried out in a single cylinder, four-stroke and direct injection diesel engine. According to the test results engine performance and exhaust emission characteristics were investigated and compared with the reference diesel fuel. Engine torque decreased and brake specific fuel consumption increased by using JP-8 blends according to the reference diesel fuel. While CO and smoke emissions increased, NOx emissions decreased with JP-8 blends when compared with diesel fuel.