This paper reports experimental phase equilibrium data for the systems {CO2 (1) + solketal (2)) and {CO2 (1) + solketal (2) + oleic acid (3)}. The phase transition pressure measurements for ternary mixtures were carried out by injecting a known amount of carbon dioxide into a mixture with fixed molar ratios of the two other components (0.75 solketal + 0.25 oleic acid). A variable-volume cell with a front window was used for the measurements. The experimental data were measured over the temperature range from (308 to 338) K and at pressures of up to 20 MPa. Bubble point conditions were measured for the binary system {CO2 (1) + solketal (2)), whereas bubble and dew point conditions were measured for the ternary system {CO2 (1) + solketal (2) + oleic acid (3)). Phase equilibrium modeling with the Peng-Robinson equation of state was successful in describing the behavior of the investigated systems.