Kinetic measurements of the sodium nitrate(III) inversion with the nitric acid(V) process, carried out in the range of c(0NaNO2): 0.25-0.5 mol/dm(3) c(0OHNO3): 1.5-3.0mol/dm(3), T = 303-353 K, Re 8500, were presented. A reaction rate equation and Arrhenius equation parameters were determined on the basis of the results obtained. It was found that in the examined parameter ranges the overall process rate could be described by a second-order kinetic equation. (C) 2003 Elsevier Science B.V. All rights reserved.