Abstract: A homogeneous combustion engine fuel extender fuel formulation has been provided for blending with gasoline as a relatively inexpensive substitute therefor in an amount of not greater than about 50% by volume. Although employing ethanol and naphtha, it is formulated in such a manner that disadvantages of naphtha and ethanol as used alone have been avoided and that gasoline containing the extender will have substantially the same working characteristics as commercial leaded and unleaded gasoline, requiring no changeover or adjustment of engine components when used alternately with 100% commercial gasoline. Basically, the formulation involves a critical solution content of an aliphatic naphtha, ethanol and a higher alcohol.