INTRODUCTIN: This report provides information on certain fuels that are being used or have been suggested as alternatives to motor gasoline (SAE J312. Automotive Gasolines) or automotive diesel fuel (SAE J313 Diesel Fuels) for use in spark-ignition or compression-ignition engines. Some of these fuels are derived from petroleum while others are from non petroleum sources. Other than gasoline@ the fuels commonly used in spark-ignition engines are propane@ frequently refereed to as LPG (liquefied petroleum gas); gasohol (Reference 1) ?C a blend of 90% by volume unleaded gasoline and 10% by volume denatured@ nominally anhydrous ethyl alcohol (ethanol); leaded gasohol ?C a blend of 90% by volume leaded gasoline and 10% by volume ethanol; and gasolines containing methyl and tertiary butyl alcohol. Possible alternative fuels include compressed or liquefied methane@ and other alcohols and ethers@ either neat or blended into gasoline. The ethers and alcohols and ethers@ either neat or blended into gasoline. The ethers and alcohols are used as octane improving agents and fuel extenders. Ethanol of 92.5 ?C 93.8% by weight alcohol content is used as the fuel in many of the cars currently manufactured in Brazil. Methyl alcohol (methanol) is used in some European gasolines@ is currently being evaluated in may countries@ and is also widely used a s racing fuel. Except when used at low concentrations of less than 15% by volume as blending agents in gasloline@ these alternative fuels required engine and/or vehicle modifications@ and may also require changes in lubricating oil characteristics to provide optimum engine durability. Distribution and storage facilities may also have to be modified. Only diesel fuel is used in compression-ignition engines at present. One practical alternative is a wide-boiling range petroleum fuel. Use of such fuel would likely require some engine and/or vehicle changes@ but would probably not require any changes in distribution or storage facilities. Fuel derived form biomass sauces are being widely investigated as a means of extending diesel fuels.