The kinetics of redox reduction of Toluidine blue (hereafter referred to as TB+) by dithionate ion have been studied in acidic medium under pseudo-first order condition of excess [S2O6 2-] at 31± 1oC, [H+] = 1 x 10-2 mol dm-3, ionic strength (I) = 0.5 mol dm-3 (NaCl) and λ max 600 nm. The redox reaction displays a 1:1 stoichiometry and the reaction was found to be first order and 3/2 order in the oxidant and the reductant respectively. The reaction is also catalyzed by hydrogen ion with the empirical rate law as.