This article predicts the optimum conditions for the production of fatty acid ethyl ester (Biodiesel) by trans-esterification process of waste cooking sunflower oil with ethanol in the presence of homogeneous catalyst (KOH). Response surface methodology (RSM) based on central composite rotatable design (CCRD) was used for predicting the mathematical regression equation and optimizing the biodiesel yield. The optimum reaction conditions were found to be 9.05 (mole mole(-1)) of (ethanol to waste cooking sunflower oil ratio), 0.99 (wt% to oil) of catalyst concentration, 57.31 degrees C of reaction temperature, 77.12 minutes of reaction time, and 494.94 rpm of mixing rate to achieve 96.33% biodiesel yield by weight. The production rate of produced biodiesel also increased significantly. The fuel properties were measured and found closer to the ASTM standards of biodiesel. Therefore, the suggested biofuel has good scope for use in compression ignition (CI) engines.