Some investigations on the preparative procedures of fibrous polystyrene thorium(IV) phosphate (PStThP) are reported. This new fibrous ion exchanger has been characterized on the basis of scanning electron microscopy, X-ray diffraction analysis, IR, thermogravimetric analysis, and ion exchange studies. The ion exchange capacity for Naf ion is found to be 4.52 mequiv/dry g basis. Separation factors and Kd values for various cations at different concentrations have been determined, and a marked selectivity for Cd(II) has been found. The unusual selectivity for Cd(II) should lead to some useful practical applications.