In this study, an experimental investigation was performed in order to determine the effects of Jet-A1(A100), diesel fuel and Jet-A1/diesel fuel blends (A25, A50, A75) including 25% Jet-A1/75% diesel, 50% Jet-A1/50% diesel and 75% Jet A1/25% diesel by volume respectively on combustion and engine performance in a single cylinder, direct injection diesel engine. For this purpose, the test engine was run at four different brake torques (7.5, 11.25, 15 and 18.75 Nm) at maximum brake torque engine speed (2200 rpm). The variation of cylinder pressure, heat release rate, ignition delay, combustion duration and exhaust emission were investigated in a naturally aspirated direct injection diesel engine fueled with diesel-Jet-A1 fuel blends. The test results showed that ignition delay time decreased with the increase of brake torque. Maximum in-cylinder pressure was retarded versus crank angle with the increase of brake torque. NOx emissions decreased with the increase of amount of Jet-A1 in the test fuels, but CO and soot emissions increased. It was also found that combustion duration increased when Jet-A1 (A100) fuel was used compared to A25, A50, A75 test fuels. In conclusion, Jet-A1 aviation fuel can be utilized via mixing with diesel fuel in diesel engines.