The effect of the dioxygen and beta-picoline concentrations on the oxidation of beta-picoline to nicotinic acid was studied at 270 degrees C over a 20% V2O5 - 80% TiO2 (wt. %) catalyst. The study was performed in a differential reactor at constant concentrations of water and nicotinic acid. A considerable excess of dioxygen was shown to be necessary for the formation of nicotinic acid. It was found that the rates of P-picoline transformation into nicotinic acid, pyridine-3-carbaldehyde, pyridine-3-nitrile, pyridine and carbon oxides as well as selectivities to products and the catalyst state depend strongly on the ratio of dioxygen to P-picoline concentrations. The minimum admissible ratio of these concentrations under industrial conditions was determined.