Basic properties are reported for a previously undocumented biofuel mixture of refined, bleached and deodorized soybean oil-butanol and its pure components according to ASTM standards. Kay's mixing rule was used to predict relative density and higher heating values based on mixture composition while the Grunberg-Nissan approach was used to predict the viscosity-composition relationship. Absolute average deviation values of <5.1%, <0.028% and <0.012% were obtained for viscosity, higher heating value and relative density, respectively. Temperature dependency was found to be linear for relative density and surface tension yielding R-2 values of >.994 and >.97 from linear regression. Viscosity exhibited an exponential relationship with temperature. The Andrade equation was shown to be the appropriate representation with absolute average deviation values <1.25%. Cloud point, pour point and cold filter plugging point were measured. Increasing the concentration of butanol decreased the cloud point, pour point, and cold filter plugging point. Cloud point and cold filter plugging point experienced the most significant change at butanol concentrations <25%. Values stayed almost constant for concentrations beyond that. The pour point continued to decrease with increasing butanol concentrations. (C) 2012 Elsevier Ltd. All rights reserved.