Equilibrium isotherms and kinetics of adsorption of n-paraffin wax from isooctane solution on crystalline urea were obtained at 50 and 70-degrees-C and at 50, 70, and 90-degrees-C, respectively. The equilibrium data were correlated according to the Polanyi potential theory, which provided a single characteristic curve of the experimental data at two temperatures. The batch kinetic data suggest that the adsorption of n-paraffin wax on crystalline urea is diffusion controlled. Effective diffusion coefficients derived from fractional uptake versus time were in the order of 10(-14) to 10(-13) cm2/s. The apparent activation energies of diffusion decreased with increasing uptake, as expected.