Isothermal gas solubility data (P, x data) for (oxygen + acetonitrile) were measured with a static synthetic method at temperatures of (305.51, 323.12, and 353.13) K. From these data, Henry coefficients were derived. The obtained data were used to optimize group interaction parameters for the PSRK group contribution equation of state. The data are presented together with the obtained calculations. (C) 2004 Elsevier Ltd. All rights reserved.