Soil and sediment contamination with hydrocarbons is an environmental concern, which demands for more efficient remediation techniques. Pure and modified supercritical carbon dioxide (SC CO2) was used for the extraction of petroleum hydrocarbons from soil contaminated with crude oil. Effect of CO2 flow rate (1 and 4 ml/min), temperature (80 and 160 °C), pressure (250 and 350 bar), and addition of 5% (v/v) organic solvent (heptane or toluene) on the extraction efficiency and on the composition of extracted hydrocarbons were investigated. The maximum extraction efficiency (92.26%) was obtained at 80 °C and 350 bar corresponding to a modified CO2 with 5% (v/v) heptane. Extraction efficiency of C02 increased with pressure and decreased with temperature. Chemical modification of C02 by adding heptane increased the extraction efficiency. Analysis of the soil after the extraction process shows that pure SC CO2 was able to remove up to 92.86% of TPH in the contaminated soil. In addition, a significant reduction in PAH level was observed. Supercritical fluid extraction proved to be an efficient method for the remediation of hydrocarbon-contaminated soil.