The phase behaviour of the {CO2 (1) + cis-decalin (2)} binary system has been experimentally studied at temperatures ranging from (292.75 to 373.75) K. Saturation pressures, ranging from (15.9 to 490.5) bar, were obtained using a variable volume high-pressure cell by visual observation of phase transitions at constant overall composition. For this system, no literature data are available and the results obtained in this study reveal the occurrence of vapor-liquid, liquid-liquid, and vapor-liquid-liquid phase transitions in the investigated temperature range. A total of 133 experimental points are reported including bubble points, dew points, liquid-liquid phase equilibria, and coordinates of the three-phase line. The experimental data can be reasonably predicted by the PPR78 model in which the temperature-dependent binary interaction parameter is calculated by a group contribution method. (C) 2008 Elsevier Ltd. All rights reserved.