Experiments were conducted to study the ability of surfactant-modified clinoptilolite for molybdate adsorption from aqueous solutions. Clinoptilolite was treated with some cationic surfactants. Adsorption of surfactants on zeolite surface was confirmed by chemical analysis, IR (Infra-Red Spectroscopy), DTG (Derivative Thermogravimetry) and SEM (Scanning Electron Microscopy) techniques. The modified zeolites were reacted with molybdate solutions having a known activity of radionuclide 99Mo. The results indicated that surfactant modification enhances the ability of zeolite for molybdate adsorption, particularly at pHs lower than 5.5. Adsorption capacity of modified zeolite depends on the surfactant type. The presence of studied anions always reduced the adsorption of molybdate whereas Cs+ increased it. Desorption studies showed that surfactant-modified clinoptilolite is a good candidate for removal and immobilization of 99Mo.