Oil extraction from crushed Crotalaria Juncea seeds is done by standard solvent extraction method using a modified Soxhlet apparatus. Parameters such as size fractions of the crushed seeds, extraction time, aging of seeds, choice of solvents and use of co-solvents along with the primary solvent are optimized in order to enhance the yield of bio oil production. The bio-oil is characterized using Fourier Transform Infrared Spectroscopy (FT-IR) and Gas Chromatography Mass Spectrometry. Further, some tests for the elemental analysis for Carbon, Hydrogen, Nitrogen and Sulphur, moisture content, residual carbon and dynamic viscosity are executed. Some of the basic fuel properties such as specific gravity, iodine number, saponification value, calorific value, flash point, fire point and kinematic viscosity are investigated to characterize fuel quality of the bio-oil. Though the energy content of the Sunn Hemp oil (34.128 MJ/kg) is slightly lower than that of gasoline (47 MJ/kg) and diesel fuel (44.8 MJ/kg), other fuel properties indicate that there is a great prospect for using this bio oil as a fuel for a diesel engine after some modifications. (C) 2013 Elsevier Ltd. All rights reserved.