In this study, the effects of the usage of soybean oil on bituminous binder properties have been examined and the hot mixture performances of binders modified with soybean oil have been evaluated differently from the studies in the literature. Modification of bitumen with soybean oil was carried out at 1 %, 2 % and 3 % additive ratios, at 160 degrees C temperature, using a mixing speed of 2,000 rpm for 60 minutes. Conventional bitumen tests and adhesion and stripping tests were applied on both reference binder and bituminous binders modified with soybean oil. In addition, optimum bitumen contents, indirect tensile strengths, and moisture susceptibilities of hot mix asphalt samples prepared with bituminous binders modified with soybean oil have been determined by using the Superpave Volumetric Mix Design. According to the results, the consistency and viscosity of the binders decreased as the amount of soybean oil added to the bituminous binder increased. In addition, while the maximum indirect tensile strength was achieved for the 1 % soybean oil additive, an increase in resistance to moisture susceptibility was observed for all additive ratios.