The optimal conditions for lipase production were determined by response surface methodology in solid state fermentation with Aspergilles niger. A second-order central composite design was applied to evaluate the effects of four independent variables incubation time, pH, olive oil concentration as inducer effect and yeast extract concentration on the lipase activity. Correlation analysis of the mathematical regression model indicated that the quadratic polynomial model could be employed to optimize the lipase production. The linear term of incubation time, olive oil and yeast extract concentration had significant effects on production of lipase (p-value < 0.05). Maximum lipase activity from the experimental was determined to be 69.78 U/g under the optimal conditions.