Experimental solid-liquid equilibrium (SLE) data for the binary system methacrylic acid-methanol in the high concentration range of methacrylic acid were obtained and correlated using several methods. The heat of solution of methacrylic acid was obtained from the results. Several methods of determination of SLE categorized into two kinds of activity coefficient treatments were also studied. The former methods were the modified UNIFAC (Dortmund) model and the calculation from solubility parameters under regular solution assumption using predicted activity coefficients. The later were the NRTL equation and the lambda h equation estimating the heat of solution and activity coefficients directly by fitting the experimental SLE data. Based on the results, the recommended method of determination for this system was discussed. (C) 2011 Elsevier B.V. All rights reserved.