A non-petroleum fuel derived from oil shale was evaluated with respect to the reference petroleum based Diesel fuel. Tests were conducted using a cylindrical water cooled furnace to compare these fuels on the bases of combustion efficiency, heat transfer to the water jacket and gaseous and particulate emissions over a wide range of air-to-fuel (A/F) ratios at different levels of energy input. The results showed that the rate of heat transfer to the water jacket of the furnace and, hence, the combustion efficiency was improved in the case of shale oil compared to Diesel fuel when the fuels were tested under the same A/F ratio and the same amount of energy input to the furnace. Also, shale oil had higher NOx levels at the lean side of operation but lower particulate emissions in the lean side of operation.