The solubilities of ethylene in the methyl acetate (MA) solutions of poly (ethylene-co-methyl acrylate) (EMA) were investigated according to conditions applicable to polymerization. The bubble point pressure (BP) for vapor-liquid equilibrium (VLE) and the cloud point pressure (CP) for liquid-liquid equilibrium (LLE) of ethylene + MA + EMA ternary system (weight ratio of MA: EMA, 9: 1) were measured at temperatures of 373 K and 393 K and at pressures up to 25 MPa with a synthetic method. The BP and CP increased with increasing temperature and ethylene weight fraction, especially the slope of CP against ethylene weight fraction was large. The Sanchez-Lacombe equation of state (SL EoS) could correlate VLE data of ethylene + MA and ethylene + EMA systems by fitting a corresponding binary interaction parameters for each binary to within about 4.7% in pressure. The phase equilibria of the ternary system could be predicted with the SL EoS from binary interaction parameters determined from the binary systems. (C) 2018 Elsevier B.V. All rights reserved.