The kinetics of the oxidation of xylenol orange tetrasodium salt by hydrogen peroxide was investigated in the presence of cationic surfactant (N-dodecylpyridinium chloride) & strongly basic media over the temperature range 20 - 35 °C. The kinetics studies were carried out as a function of different variables like concentration, pH and temperature. The described reaction rate is greatly catalyzed by the presence of trace amount of Co(II) ions & followed pseudo-second- order with respect to dye concentration. Possible mechanism for the catalyzed and uncatalyzed reactions is proposed and found to be coincident with the experimental findings. The derived rate equation is in good agreement with the experimental observations. Thermodynamic parameters were also evaluated.