Xanthan production is influenced by the type and initial concentration of the carbon and nitrogen source as well as by the phosphate and citrate concentrations added. An optimal and industrially useful fermentation medium has been devised. It consists of either glucose (4.0%), sucrose (4.0%) or sirodex A (2.8%) as a sole carbon source, corn steep liquor (2.0%) as a combined nitrogen-phosphate source and additional phosphate (0.1%) and citrate (0.1%) depending on the application of the xanthan formed.