The effect of dissolved poly(lactic acid) (PLA) on the solubility of gases (CO2, N-2, and He) in dichloromethane (CH2Cl2) was investigated, between 288 and 303 K, by measuring the equilibrium pressure in a closed vessel containing a gas and CH2Cl2 solutions of different types (molecular weights) and concentrations of PLA. The results show that, in the absence of PLA, the order of the solubility of gases in dichloromethane was He < N-2 < CO2. Furthermore, an increase in the concentration of PLA did not appreciably change the solubility of CO2 in the solutions but led to a higher solubility of N-2 and He. The effect of PLA on the increase of gas solubility in CH2Cl2 was larger for less soluble gases. Semiempirical correlations of the dependence of the Henrys law constant of the gases on the temperature and PLA concentration were also derived from the measured data.