Blended fuels were obtained with isobutanol contents of 10, 20, 30, 40, 50, 60, 70, 80, and 90 vol % with pure gasoline fuel. The physical and chemical properties of isobutanol-gasoline blends were investigated using test methods from standards and codes or calculation. No phase separation occurred in isobutanol-gasoline blends at specific temperatures, and isobutanol and gasoline could be blended successfully in every ratio volume. The blended fuel properties were determined, that is, density, low heating value (LHV), 10% volume fraction, kinematic viscosity, stoichiometric air/fuel ratio, octane number, copper corrosiveness, and oxygen content. Moreover, the results of the density, LHV, and octane number of the isobutanol-gasoline blends obtained from calculations can be used as a reference, but the results of the kinematic viscosity cannot. (c) 2014 American Institute of Chemical Engineers Environ Prog, 34: 908-914, 2015