Isothermal vapour-liquid equilibrium measurements for mixtures containing cyclic ethers: tetrahydrofuran, tetrahydropyran, 1,3-dioxolane or 1,4-dioxane and 1-chloropentane at the temperatures of 298.15, 313.15 and 328.15 K are reported. The thermodynamic consistency of the VLE measurements was satisfactorily checked with the van Ness method. Activity coefficients were correlated with Wilson, NRTL, and UNIQUAC equations. The calculated excess Gibbs functions for tetrahydrofuran and tetrahydropyran are negative over the whole composition range while for 1,3-dioxolane and 1,4-dioxane the excess Gibbs functions are positive. (c) 2006 Elsevier B.V. All rights reserved.