Generalized expressions for the interaction coefficients (k(ij)) of CH4/hydrocarbon binary systems are presented for a modified and translated Peng-Robinson equation of state (t-mPR). The correlations involve the acentric factor of the heavier hydrocarbon and cover the CH4/n-alkane systems up to n-C-44 plus isomers and cycloalkanes. Typical errors in bubble point pressure predictions are below 5%, similar to those obtained by fitting the T-P-x data. Successful predictions of saturated liquid and vapor volumes are also obtained. For the CH4/non-alkane systems average k(ij) values are recommended, since the lack of data for an adequate number of systems does not allow the development of a generalized correlation. The proposed correlations can be used with the Peng-Robinson equation of state as well.