The kinetics of esterification of lactic acid with methanol in the liquid phase are studied by using a cation exchange resin in the H+ form (DOWEX-50W) as an acid catalyst. Experiments were carried out in a stirred batch reactor at different temperatures (323, 333, 343, 353 K) under atmospheric pressure, The effects of reaction temperature and catalyst loading on the reaction rate are investigated, It is found that catalyst size and stirring speed have no significant effects on reaction fate. The reaction rate data are correlated with a kinetic model based on pseudo-homogeneous catalysis. The activity of resin is compared with that of sulfuric acid as a catalyst. A kinetic equation for describing the reaction catalyzed by cation exchange resin is developed.