The vapour pressure of pure components and isothermal (vapour + liquid) equilibrium data at temperatures of (343.15, 353.15, and 363.15) K for binary mixtures containing (cyclopentanone or cyclohexanone with 1,1,2,2-tetrachloroethane) are reported. Use has been made of an ebulliometer which allowed sampling from both phases in equilibrium. Both systems exhibit azeotrope with minimum pressure at all three temperatures. The experimental data were correlated using the Redlich-Kister, Wilson, NRTL and UNIQUAC models by means of maximum likelihood method. The systems show negative deviations from ideal behaviour. (c) 2006 Elsevier Ltd. All rights reserved.