Experimental phase equilibrium data for binary systems involving epsilon-caprolactone, delta-hexalactone, and gamma-caprolactone with carbon dioxide have been measured applying the synthetic method using a high-pressure, variable-volume view cell over the temperature range of (303 to 343) K and pressures up to 21 MPa. For the systems investigated, (vapour + liquid) (VLE), (liquid + liquid) (LLE), and (vapour + liquid + liquid) (VLLE) equilibrium were visually recorded. It was observed that an increase in temperature or in carbon dioxide concentration led to a pronounced raise in transition pressure values. The experimental results were modelled using the Peng-Robinsom equation of state with the conventional quadratic mixing rule, affording a satisfactory representation of the experimental values. (C) 2009 Elsevier Ltd. All rights reserved.