Abstract: This study was carried out to determine the effects of pressure, temperature, pressing time and moisture content on the yield of oil mechanically expressed from Pistacia atlantica Desf. seeds using a hydraulic press conceived at our laboratory and made in Algeria. The ground sample is compressed at various pressures (50-90 and 120 bars) and temperatures (25-40 and 60°C). The effect of thickness cake, pressing time and moisture content was determined at 120 bars and 25°C. The oil expressed was collected and the oil yield was estimated as a percentage of the raw sample before expression. Statistical analysis of effect of these parameters on yield oil was carried out by student’s t-test. Effect combined of pressure and temperature was evaluated using Response Surface Methodology. Chemical proprieties of Pistacia atlantica Desf. seeds were determined. Physicochemical analysis of the oil was also carried out to determine its quality potential. The optimum parameter values for maximum oil yield (44, 17%) from seeds were the following: moisture content during pressing = 3.95%, pressing time = 60 min, pressing pressure = 120 bars and temperature during pressing = 40°C.