alternative fuels with vegetarian basis to be the focus of . The oil composition consists of mainly palmitic, stearic, oleic and linoleic fatty acids which can be changed to biodiesel. One of the usual methods for oil extraction is Soxhlet. But due to liquid solvent toxicity, very high amount of usage and process inability for complete recovery, its application is not recommended. Employing novel method of extraction via supercritical fluid because of different environmental, scientific and economical advantages has attracted the interest of researchers investigating different separation processes. Therefore, supercritical carbon dioxide was used for extraction of Jatropha seeds oil. In this study, the experimental design was applied to carry out extraction process at different operating conditions by response surface methodology (RSM) and central composite design. So the effect of four main extraction variables of temperature, pressure, SC-CO 2 flow rate and dynamic time were investigated on the extraction recovery and yield in the range of 40-60 °C, 200-300 bar, 1-2 ml/min and 40-160 min, respectively. For production of biodiesel from extracted oil, transesterification method was used in which fatty acids were converted to fatty acid methyl esters (FAMEs) by using a catalyst. In this study two certain acidic and alkali catalysts were employed that higher yield for transesterification reaction was obtained via alkali catalyst in contrast to acidic catalyst. The results of extraction and esterification processes are demonstrated in response variables such as extraction yield, oil and biodiesel (the total combination of FAMEs) recovery. Adjusted R 2 for quadratic model of oil recovery was calculated to be 97.6%. Moreover, this value for model of palmitic, stearic, oleic, linoleic methyl esters recovery and biodiesel recovery were obtained to be 90.5, 92.4, 92.0, 92.5 and 95.2%, respectively. In addition to design and data analysis, optimization of operating conditions was also carried out by RSM. Accordingly, optimum temperature, pressure, SC-CO 2 flow rate and dynamic time were obtained to be 55°C, 300 bar, 1.74 ml/min and 160 min, respectively. At the aforementioned optimum conditions maximum oil recovery of 82.7% was achieved. Additionally, at the optimum conditions of 52°C, 300 bar, 1.64 ml/min and 160 min, the maximum recovery of FAMEs (palmitic, stearic, oleic and linoleic) and biodiesel were determined to be 94.7, 75.9, 75.9, 77.7 and 79.4%, respectively. In addition to RSM analysis, mathematical modeling based on differential mass balance for stationery (Jatropha) and mobile (SC-CO 2 ) phases was derived and solved using backward, central and forward finite difference method. The developed model contained a linear equilibrium relationship in Jatropha pores and three parameters such as film mass transfer coefficient, effective diffusivity and axial dispersion coefficient. The modeling predictions were compared with experimental data in which the model was validated due to a very close compatibility (R 2 = 0.967). Furthermore, the aforementioned validated model was utilized for analysis of important extraction variables. In this study, the effect of variables such as dynamic extraction time, temperature, pressure and flow rate of SC-CO 2 on recovery of biodiesel was investigated using the validated model. The experimental and modeling data indicated that higher pressure led to increased recovery. This observation and prediction is due to higher density of SC-CO 2 at elevated pressure which resulted to increased solubility of CO 2 . Moreover, higher CO 2 flow rate also increased the extraction recovery. This trend is because of reduction of film mass transfer thickness around Jatropha particles. Lower film thickness resulted in decreased mass transfer resistance and consequently enhanced mass transfer coefficient. In regard to flow rate, it should be noted that higher flow rate decreases extraction column residence time which obviously has a negative effect on recovery. But in the flow rate operating range of this research, the dual counter effect parameters has a shift toward higher mass transfer coefficient with respect to lower residence time. In addition to two mentioned variables, higher temperature also led to increased recovery. Also in this case other dual counter effect parameters of high FAMEs vapor pressure and low CO 2 density are applicable. In other words, the retrograde solubility phenomenon has the vital role in determining the maximum recovery.