Xanthan gum is an extracellular polysaccharide produced by various Xanthomonas species such as X. campestris. The objective of present study was to investigate the influence of different carbon and nitrogen sources on xanthan gum production by X. campestris. Using an ex- perimental Response Surface Methodology (RSM) complemented with a Central Composite De- sign (CCD), the impact of peptone, lactose, glucose and ammonium nitrate in medium were esti- mated for their individual and interactive effects on biomass and xanthan gum production. The optimal concentrations of peptone, lactose, glucose and ammonium nitrate for xanthan gum yield and biomass production was determined as 9.25 g/l, 53.37 mmol, 29.31 mmol and 4.58 g/l for xan- than gum yield and 6.77 g/l, 52.65 mmol, 38.12 mmol and 3.54 g/l for biomass production. Under the optimum experimental conditions, the xanthan gum yield reached to its maximum value (8.42 g/l). The results provide the support data for xanthan gum production on a large scale.