Sorption and diffusion of some aldehydes and ketones into interpenetrating polymer networks (IPNs) of polyurethane-polystyrene (PU-PS) have been investigated in the temperature interval of 25-60 degrees C. Transport data were found to be affected by the nature of the interacting solvent molecule rather than its size. The diffusion coefficient of ketones range from 9.2 x 10(-8) to 645 x 10(-8) cm(2)/s and for aldehyde from 11.5 x 10(-8) to 154.5 x 10(-8) cm(2)/s. For all solvents, the polymer remained intact. From the temperature dependence of sorption data, the Arrhenius activation parameter and the thermodynamic parameter, such as entropy and enthalpy for the process of equilibrium sorption, have been estimated.