A fully continuous lab scale supercritical fluid extraction system has been designed, built and tested. The system continuously pumps carbon dioxide under supercritical conditions and soil slurry into a counter-current contacting column. Delhi Loamy Sand, spiked with approximately 10 mg/g of naphthalene, was used as the testing soil. The soil slurry ranged from 0.0028 g dry soil per g slurry to 0.072 g/g. The operating temperature was 43 degrees C and the operating pressure was 7.7 MPa. Near steady state, fully continuous flow was achieved with runs lasting as long as 2 h. All carbon dioxide samples contained measurable quantities of naphthalene and the measured mass transfer coefficients were as high as 4.6x10(-4) s(-1).