Medium optimization for the nuclease (RNase) production by Bacillus firmus VKPACU-1 was studied using the one-factor-at-a-time method and Response Surface Methodology (RSM). One-factor-at-a-time methodology was used to study the effects of carbon, nitrogen, phosphorus sources, and physical conditions such as pH and temperature, on nuclease (RNase) production. After optimizing the carbon (glucose) and nitrogen (tryptone) sources in the culture medium the physical conditions, pH (6.5) and temperature ($35^{circ}C$) were also optimized. Later these conditions were chosen as the main factors and used in the experimental design. The central composite design (CCD) of the RSM was employed to evaluate the interactive effects of these four variables. The optimized values obtained by the statistical analysis showed that glucose 5.95 g/L, tryptone 22.5 g/L, pH 6.5, and temperature $35^{circ}C$ affected maximum nuclease (RNase) production. When utilizing these proposed optimized conditions, the model predicted nuclease (RNase) production of 43.6 U/mL and in the validation experiments, the nuclease production obtained was 46.5 U/mL. The nuclease production in medium optimized by RSM was 26% higher, than in the non-optimized medium.