Abstract: Anodization of zircaloy-4 in 0.1M ammonium oxalate has been carried out. Kinetics of anodic oxidation of zircaloy-4 has been studied at a constant current density of 8mA.cm-2 and at room temperature. Thickness estimates were made from capacitance data. The plots of formation voltage vs. time, reciprocal capacitance vs. time, reciprocal capacitance vs. formation voltage and thickness vs. formation voltage were drawn. From these plots rate of formation; current efficiency and differential field were calculated. The addition of solvent (methanol) showed better kinetics results. For 25%, 50% and 75% aquo-methanolic media, the dielectric constant values are low leading to a marked improvement in the kinetics. In 80% methanol, though the dielectric constant value of solution is less, the kinetics was slow which may be attributed to the fact that the electrolyte becomes highly non-polar.