Bacteria Thiobacillus (Th.) denitrificans belongs to gram-negative, obligate chemolithoautotrophic and facultative anaerobic microorganisms. Th. denitrificans uses the oxidation of reduced inorganic sulfuric compounds for the respiratory reduction of nitrates or nitrites under anaerobic conditions. Denitrification can be affected by many factors. The aim of the work was to describe the positive influence of different concentrations of phosphorus and molybdenum to autotrophic denitrification by Th. denitrificans, and to determine optimal amount phosphorus and molybdenum for specific conditions. The best added concentrations of phosphorus was from 1,0 to 1,5 mg / l and molybdenum was 0,1 mg/l for autotrophic denitrification of bacteria Th. denitrificans in tested batch reactors.