Computer simulations are used to simulate the adsorption isotherms of methane, ethane, and propane in the zeolite silicalite. Various zeolite-alkane models have been tested via a comparison with experimental heats of adsorption and Henry coefficients. These tests are used to improve the existing models. It is shown that the calculated adsorption isotherms agree well. with the available experimental data. However, a definitive validation of the models is impeded by the large scatter of reported experimental data.