Supercritical fluid extraction of jojoba oil from Simmondsia chinensis seeds using CO2 as the solvent is presented in this study. The effects of process parameters such as pressure and temperature of extraction, particle size of jojoba seeds, flow rate of CO2, and concentration of entrainer (hexane) on the extraction yield were examined. Increases in the supercritical CO2 flow rate, temperature, and pressure generally improved the performance. The extraction yield increased as the particle size decreased, indicating the importance of decreasing intra-particle diffusional resistance. The maximum extraction yield obtained was 50.6 wt% with a 0.23-mm particle size and a 2 mL/min CO2 flow rate at 90degreesC and 600 bar. Use of an entrainer at a concentration of 5 vol% improved the yield to 52.2 wt% for the same particle size and also enabled the use of a relatively lower pressure and temperature, i.e., 300 bar and 70degreesC.