Supercritical carbon dioxide (SC-CO2) extraction of flaxseed oil was performed and effects of process parameters including particle size (mean particle diameter <0.85-0.92 mm), solvent flow rate (2-4 g/min), pressure (40-60 MPa) and temperature (50-70 degrees C) were investigated. The broken and intact cells (BIC) model was used for mass transfer modeling of the extraction of flaxseed oil with SC-CO2 successfully. Extraction of flaxseed oil was divided into two periods as first (fast) and second (slow) extraction periods. Great part of the flaxseed oil was extracted in the first period and a very small amount was extracted in the second period. Decreasing the particle size increased the amount of released (free) oil. Increasing the pressure, temperature and flow rate also caused slight increases in the released oil amounts. Increase in the solvent flow rate, pressure and temperature increased the extraction rate in the first period within the range of experiments. The fluid phase mass transfer coefficient (k(f)a) varied between 0.38 and 2.32 min(-1) and the solid phase mass transfer coefficient (k(s)a) varied between 0.5 x 10(-3) and 6.7 x 10(-3) min(-1). (C) 2016 Elsevier B.V. All rights reserved.