Extraction of sunflower oil from sunflower seeds (Heliantus annuus L.) using supercritical CO 2 was studied. The shrinking core model was applied to the modeling of the packed-bed extraction process. The experimental data were obtained for extraction conducted at the pressures of 20, 30, 40, 50 and 60MPa; the temperatures of 313, 333 and 353K, the CO 2 flow rates of 1–4, and 6cm 3 CO 2 min −1 ; the mean particle diameters of 0.23, 0.55, 1.09, 2.18mm. The supercritical CO 2 extraction process was modeled by a quasi steady state model as a function of extraction time, pressure, temperature, CO 2 flow rate, and particle diameter. The supercritical CO 2 extraction process. The intraparticle diffusion coefficient (effective diffusivity) D e was used as adjustable parameter. The model using the best fit of D e was correlated the data satisfactorily.