In this research, the bioremediation of dispersed crude oil, based on the amount of nitrogen and phosphorus supplementation in the closed system, was optimized by the application of response surface methodology and central composite design. Correlation analysis of the mathematical-regression model demonstrated that a quadratic polynomial model could be used to optimize the hydrocarbon bioremediation (R 2=0.9256). Statistical significance was checked by analysis of variance and residual analysis. Natural attenuation was removed by 22.1 of crude oil in 28 days. The highest removal on un-optimized condition of 68.1 were observed by using nitrogen of 20.00mg/L and phosphorus of 2.00mg/L in 28 days while optimization process exhibited a crude oil removal of 69.5 via nitrogen of 16.05mg/L and phosphorus 1.34mg/L in 27 days therefore optimization can improve biodegradation in shorter time with less nutrient consumption. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.