The solubility of thiophene (1) in CO2 (2) and in CO2 (2) + ethanol (3) mixtures were measured from (313 to 363) K using a static-analytical method connected on-line to a gas chromatograph. The solubility of thiophene in CO2 was obtained at (314.53, 334.12, and 363.55) K. Isothermal solubilities of thiophene in CO2 + ethanol mixtures with mass fractions of ethanol (w(3)) on a solute-free basis of 0.0245, 0.0548, and 0.0820 were obtained at (333 and 363) K. The solubility of thiophene was not greatly enhanced when ethanol was added to CO2 at any composition. The experimental results were compared with those calculated values from Peng-Robinson equation of state using classical mixing rules.