The bubble-and dew-point behavior of the carbon dioxide (1) + tetrahydrofuran (2) + water (3) system has been studied. Pressure-temperature isopleths were measured for the ternary system at x1) 0.01,0.02,0.03,0.04,0.09, and 0.27 at a constant mole fraction of tetrahydrofuran, x2) 0.05. The bubble-and dewpoint lines for the ternary systems were also measured at x2) 0.01,0.03,0.05, and 0.07 for fixed composition of carbon dioxide (x1) at 0.04 mol fraction and at x2) 0.01,0.03,0.05,0.06, and 0.09 for a fixed composition of carbon dioxide (x1) at 0.09, respectively. The pressure and temperature range from (1 to 6) MPa and (280 to 300) K, respectively. The experimental results for the ternary system have been modeled using the predictive Peng-Robinson-Stryjek-Vera (PRSV) equation of state with the Huron-Vidal-Orbey-Sandler (HVOS) mixing rule and the universal quasi-chemical activity coefficient (UNIQUAC) GEmodel. Excellent agreements have been found between the experimental and the predicted values of the bubble and dew points of the ternary system throughout the composition range studied. © 2010 American Chemical Society.