Kinetics of L-ascorbic acid oxidation by cobalt(III) complexes were studied using stopped-flow spectrophotometry in aqueous solution at 25°C. Kinetics measurements were run under pseudo-first order conditions in which the concentration of ascorbic acid is between one and two orders of magnitude greater than that of the oxidant Cobalt(III) complexes of urea, C2O42-, H20, acac, EDTA, NH3, en, phen, and NO2-, were used to study the ligand effect on ascorbic acid oxidation rate; it is found that the rate of oxidation is first order with respect to both ascorbic acid and oxidizing agents. Results show that the rate of oxidation depends inversely on both the ligand's size and its strength in the specrtrochemical series.