Flexible poly(vinyl chloride) (PVC) composites having natural zeolite clinoptillolite were prepared by plastisol-plastigel technology. Adsoption of methylene blue on each raw material and on composites was studied both from an equilibrium and a rate approach. It was observed that the adsorption capacity of zeolite decreased when it was embedded in composites. The equilibrium uptake of methylene blue increased with an increasing zeolite fraction in composites. Methylene blue was adsorbed from a 0.02 g . cm(-3) aqueous solution slowly, but was nearly adsorbed completely with a composite having a 0.3 volume fraction of zeolite, The effective diffusion coefficient of methylene blue in composites was of the order of 10(-13) m(2) . s(-1) and decreased with increasing filler fraction.