This paper describes a study of the interaction of high pressure subcritical and supercritical carbon dioxide with a series of poly(urethane) elastomers of differing hard segment content. The extent of gas absorbed by each poly(urethane) type and also the corresponding dilation of each poly(urethane) have been measured under gas pressures of up to ca. 23 MPa at 42 degrees C. The data indicates that, for this particular series of poly(urethanes), the extent of sorption and dilation are directly related to the structural properties of each polymer including the extent and characteristics of the soft phase component.