An experimental investigation was performed to find out the fuel properties including specific gravity, density, and viscosity of diesel and biodiesel fuel in the temperature range from 0 to 200 degrees C. Test fuels used were a conventional diesel, neat biodiesel (100% methyl ester of soybean oil), and their blends with blending ratios of 20%, 40%, 60%, and 80%. In order to analyze the fuel properties, the experiments were carried out at various temperatures for each of the six test fuels and the resulting measurements of the biodiesel and its blends were compared with the properties of conventional diesel fuel. In this work, the specific gravity of biodiesel fuel increased with the increase of the blending ratio of biodiesel and gradually decreased as the fuel temperature increased linearly. The density value measurement was correlated as a function of fuel temperature and blending ratio by an empirical equation. The viscosity of the test fuels was found to decrease linearly with increasing temperature and decreasing blending ratio. The kinematic viscosity. obtained by this investigation agrees well with the empirical equation which is derived from the measured results.