The oxidation of nicotinic acid (NA) over binary vanadia-titania catalysts with different contents of residual sulfate ions (0.2 and 2.8 wt. %) was Studied at 250-300 degrees C in the feed reaction mixture of the composition NA : O-2: H2O = 0.01-0.17 : 5-20 : 0-20 (vol. %), with nitrogen as a balance. The kinetic parameters of the process were determined. It was shown that even a ten-fold increase in the content of residual sulfate ions in the samples has no significant effect on the kinetics of the NA oxidation.