The physical and mechanical properties of soybean were determined at 8 to 16% moisture content. In this moisture range, grain length, width, thickness, arithmetic average diameter and geometric average diameter increased from 7.24 to 8.19, 6.79-7.12, 5.78-6.23, 6.60-7.18, 6.57-7.14 mm, respectively. The volume of grain and area of grain surface increased linearly from 130.97 to 160.32 and from 125.46 to 144.39 mm2, respectively. The sphericity, bulk density, true density and porosity decreased linearly from 0.91 to 0.87, 766.12-719.00, 983.33-905.67 kg m-3 and 22.58 to 20.61%, respectively. The angle of internal friction increased linearly from 27.37 to 31.81° with the increase of moisture content. The static coefficient of friction increased from 0.385 to 0.571, 0.304-0.441 and 0.164-0.286 for concrete, wood and galvanized steel surfaces, respectively.