The influence of particle size and solvent flow rate on the kinetics of oil extraction from soybean (eight fractions from 0.433 to 0.122 mm) was studied using hexane, simulating commercial percolation type extractor. The reduction in particle size from 0.433 mm to 0.141 mm showed an increase in the oil extractability. However, further reduction to 0.129 mm and 0.122 mm affected the extractability due to bed compaction, reducing porosity and contact area. The extractability (21.5%) of the ground mass was similar to the major mass fractions (0.239 - 0.353mm). The rate of extraction increased drastically with the solvent flow rate. The highest flow rate (9.67 mL/min) exhibited the highest mass transfer coefficient (km) 1.27×10-3 s-1 and the diffusion coefficient (De) 1.77×10-12m2/s. At 7.33 mL/min, the yield and the rate of extraction were optimal and no potential benefits were obtained at higher flow rates.