A synthetic type apparatus was designed to measure hydrogen solubility in four pure aromatic or cyclic hydrocarbons, benzene, cyclohexane, toluene, and methylcyclohexane, and two equimolar binary mixtures, benzene + cyclohexane, and methylcyclohexane + toluene. The experimental temperature was 303.15 K, and the pressure range from 0.887 to 4.827 MPa. The hydrogen solubility increased linearly with the pressure following the Henry's law. The hydrogen solubility in benzene was smaller than that in cyclohexane. Similarly, the solubility in toluene was smaller than in methylcyclohexane. In the measurement for the mixtures, the mole ratio of benzene:cyclohexane and methylcyclohexane:toluene was set to 1:1. The hydrogen solubility in the equimolar mixtures was lower than that in pure cyclic hydrocarbon, cyclohexane or methylcyclohexane. The experimental solubility data in pure hydrocarbons were correlated with the Peng-Robinson (PR) equation of state using van der Waals one fluid mixing rule. Using binary interaction parameters in the mixing rule, the hydrogen solubility in the mixtures was predicted well. (c) 2004 Elsevier B.V. All rights reserved.