The kinetics of oxidation of atrolactic acid (prepared from acetophenone) with eerie sulphate has been studied. The reaction was found to be of first order when the oxidant was used in excess and second order when the hydroxy acid was in excess. A sequence of reaction steps proposed explains satisfactorily this change in order of the reaction. The activation energy, frequency factor and entropy of activation were found to be 15·75 K.Cals/mole, 108 Sec-1 and -22·11 E.U. The rate of oxidation was retarded by H+ and also by the addition of a metal sulphate. The oxidation appears to proceed through an initial complex formation and subsequently through free radicals. The equilibrium constant of the complex and its rate of decomposition has been calculated.