Reliable data on the solubility of molecular hydrogen in chlorobenzene have been collected at temperatures from 273.2 to 443.2 K and pressures to 65 bar. Henry’s constant rendered from a preliminary analysis of the data is reported as a function of temperature. The influence of dissolved acrylonitrile-butadiene copolymer on the solubility has been established for 4.09 and 8.08 mass % solutions.