Due to concerns regarding energy security. fuel cost, and the environment, straight and processed vegetable oils are being considered as part or fill] replacement of diesel fuel in compression ignition engines. The lower heating value of a candidate fuel is an important characteristic used in energy release estimation. In this work, a convenient method of estimating the heating values of straight and processed vegetable oils based on the bond energies of their fatty acid/methyl ester constituents is proposed. The estimated lower heating values of 17 different straight vegetable oils are on the order of 37 MJ/kg and for 15 different processed fuels on the order of 38 MJ/kg. The accuracy of estimations when compared with the available experimental data is observed to be within 3%.