The present work investigates the suitability of mesua ferrea (nahar) oil seed as a source of alternative fuel in CI engines. Non-edible straight vegetable oil obtained from mesua ferrea seeds was extracted using a solvent extraction technique. A significant amount of unsaturated fatty acids was found from a gas chromatography test, which was,further ascertained by measuring the acid value. The thermo-physical and chemical properties of straight mesua ferrea oil were determined. The flash point, kinematic viscosity, and density of the straight mesua ferrea oil were found to be much higher than diesel, though the calorific value was found to be lower. The variation in thermo-physical and chemical properties of various blends of straight mesua ferrea oil and diesel were studied. The straight mesua ferrea oil blend up to 15% with the diesel met the standard specification. Based on the present study, it was concluded that due to higher viscosity and density and low volatility of straight mesua ferrea oil, it is not suitable for direct use in CI engine. However, blending of this oil with diesel up to 15% (by volume) can be used in a CI engine without any major engine modification.