The oxidation of oxalic acid by chromic acid has been studied kinetically at low pH and constant ionic strength. It has been found that the rate of the reaction is the sum of the rates of decomposition of a mono- and a di-oxalato complex of chromium(VI), the overall rate-law being of the form Rate=(K[Ox2-]+K′[Ox2-]2[H]3[CrO4H-. © 1969.