Sorption of chloromethanes (CH2Cl2, CHCl3, and CCl4) in copolymers of chloroprene with methyl methacrylate and methacrylic acid was studied using inverse gas chromatography and infra-red (i.r.) spectroscopy. The chromatographic study showed that introduction of ester and carboxylic side groups into main chains resulted in a selective increase of the solubility coefficient of chloroform and methylene dichloride, the solutes capable to form hydrogen bonds with proton accepters in polymer. Heats of formation of hydrogen bonds were determined by comparison of the partial molar heats of mixing in these systems and in reference systems where hydrogen bonding is excluded. The shifts of maxima of i.r. bands belonging to CH2Cl2 and CHCl3 and to C-O bonds of the copolymers confirmed the formation of hydrogen bonds. The variation of the solubility coefficients and the shifts of absorption bands indicated that hydrogen bonds formed by methylene dichloride are somewhat stronger than those formed by chloroform.