This study demonstrates that the ability of a polymeric sorbent to remove organic compounds from air or water can be selectively modified by chemically altering the surface of the sorbent. Amberlite XAD-4 was grafted with functional groups of varying size including: phosphonic acid, hydroxyalkylamine, polyamine, polyethylene glycol, hydrocarbon and halogenated hydrocarbon. Grafts were selected to provide a range of polarity as characterized by dipole moment, hydrogen bonding and Hildebrand solubility parameters. Homologous graft series of varied molecular weight were included to elucidate possible steric effects on selectivity of sorption Aqueous phase, monocomponent equilibrium isotherms were determined for phenol, methyl isobutylketone, 1,2-dichloroethane, toluene and benzene with a variety of grafted XAD-4 resins. Gas phase monocomponent sorption of toluene, carbon tetrachloride, and 2-propanol vapor from dry air by XAD-4 resins was evaluated from breakthrough curves. Grafting alters the sorptive capacity of XAD-4 as a function of steric factors, graft polarities and specific chemical bonding interactions. In this study, inhibition of sorption occurred when greater than 30% of the pendant groups of the original polymer were grafted or when the graft had more than eight atoms in its longest chain. Increasing similarity of graft and sorbate polar characteristics increased sorptive capacity relative to XAD-4. Conversely, decreasing similarity decreased sorptive capacity relative to XAD-4. Enhancement of sorption by grafts that can induce dipoles, or can form electron donor-acceptor complexes with sorbates, overwhelmed inhibition resulting from adverse steric or polar factors. Similarly, hydrogen bonding of water by hydrophilic grafts competitively inhibited sorption of various sorbates