Extraction of oil from Algerian crushed olive fruits was carried out using supercritical CO2. The effect of operating parameters such as pressure, temperature and extraction time on the yield of the extraction process was investigated. Positive effects of extraction time and pressure were shown, contrarily to the operating temperature effect, which was not significant. A second order polynomial was used to optimize the olive oil extraction yield as a function of the three considered operating parameters and an optimal value of 32.81 wt% was obtained at 300 bar, 60 degrees C and 180 min and was very close to the experimentally obtained yield of 33.35 wt% at the same operating conditions. Fatty acid compositions were obtained using Fatty Acid Methyl Ester (FAME) analysis method and the composition was found to be similar to that of virgin olive oil, with Oleic acid as the major component.