Supercritical CO2 extraction of essential oil from basil leaves was performed using a semicontinuous extraction procedure and a two-stage separation technique. Both a laboratory unit and a pilot plant were used, equipped with extraction vessels of 0.4-and 20-dm(3) volume, respectively. The products were collected and analyzed by GC-MS. Waxes were found in the first separator and basil essential oil in the second separator. The yield of the extraction,process was measured for three different particle sizes. A model based on the description of the mass transfer from a single spherical particle of leaf was applied. The model predictions were considered to be in fair agreement with experimental data over the entire range of experimental conditions explored.