Methyl methacrylate (MMA) is an important raw material in the polymer industries. The conventional method of producing methyl methacrylate had the disadvantages of dealing with very toxic raw material and producing large amounts of waste. A new and more environmental friendly route for producing methyl methacrylate involves carbon monoxide. Therefore, it is of significance to have accurate knowledge of the phase equilibria for mixtures of carbon monoxide and methyl methacrylate. In this study, we have determined the high-pressure vapour-liquid equilibria of this binary mixture within a temperature range of 313-318 K and pressures up to 12 MPa. Experiments were carried out using the Cailletet equipment, which is highly accurate for bubble point determination because it operates according to the synthetic method of phase equilibrium measurements. The results indicate that the solubility of CO in methyl methacrylate has an "inverse" temperature-dependence in which larger amounts of gas can dissolve in the liquid as temperature is increased at a fixed pressure. A comparison to carbon dioxide solubility in the same liquid shows that CO dissolved much less than CO2 in methyl methacrylate. The solubilities of these two gases differed up to about one order of magnitude. (C) 2012 Elsevier B.V. All rights reserved.