The kinetics of the aqueous-Phase oxidation of nitrous acid by hydrogen peroxide in the micromolar concentration range has been investigated over the pH range 1.8--3.1. The reaction yields nitric acid according to the stoichiometry: H2O2+HNO2→H++NO3-H2O. The experimentally derived rate law is given by -d2O2>/dt=d3->/dt=k+>2>2O2>, with k determined as (6.3¿1.5)¿103 M-2 s-1 at 25.1¿0.1¿C and zero ionic strength. The enthalpy of activation determined over the temperature range 10¿--35¿C at pH 2.07 and 0.08 M ionic strength is 13.3¿0.3 kcal/mol. The results obtained here are in fairly good agreement with those of earlier studies, despite large differences in the reagent concentrations employed (3 to 5 orders of magnitude). The contribution of this reaction to atmospheric formation of aqueous-phase NO3- and depletion of gas-phase HNO2 is found to be insignificant for representative atmospheric conditions; however, oxidation of N(III) by H2O2 in collected precipitation samples may be appreciable on a time scale of hours to a few days.