The aim of the present research is to study some different factors affecting the mechanical extraction of jatropha oil. The hydraulic pressing machine was evaluated using (whole seeds or kernel), four pressures of 100, 150, 200 and 250 bar, four seed cooking temperatures of 80, 90, 100 and 110 °C and four extraction times of 15, 20, 25 and 30 min. The evaluation included machine production rate, expression efficiency, oil losses, specific energy and economical costs. The obtained data showed that using the whole seeds the highest value of machine productivity of 3.43 kg/h, the lowest specific energy of 144.46 kW.h/Mg and the lowest cost per mass unit of 7.23 L.E/Mg were recorded with extraction pressure of 250 bar, extraction time of 15 minute and seed temperature of 110 °C. And the highest value of expression efficiency of 85.93% at extraction pressure of 250 bar, extraction time of 30 minute and seed temperature of 110 °C. meanwhile, using kernel seeds under room temperature the highest value of machine productivity of 4.87 kg/h, the lowest specific energy of 100.80 kW.h/Mg and the lowest cost per mass unit of 5.05 L.E/Mg were recorded with extraction pressure of 250 bar and extraction time of 15 minute. And the highest value of expression efficiency of 87.04% at extraction pressure of 250 bar and extraction time of 30 minute.