A new experimental technique has been developed to measure the solubility of gases and vapors in polymers and other sorbents at elevated pressures. The technique involves measuring the total weight of a vessel containing the sorbent material pressurized with a vapor, assessing the amount of vapor in the headspace of the vessel with an appropriate equation of state, and evaluating the total amount of vapor in (on) the sorbent material by the difference. Adsorption isotherms for carbon dioxide and nitrogen on an activated carbon were measured with the static sorption technique. These data were found to agree well with data taken with a standard volumetric technique. Sorption data obtained using this method for carbon dioxide in poly(vinyl acetate) and propylene in poly(propylene) compare well with data acquired by established techniques. The group-contribution lattice-fluid theory equation of state was used to predict solubility in these systems, and the Panayiotou-Vera equation of state was applied to correlate the solubility data.