Natural and Si rubbers were filled with Bi(2)O(3) (50-200 phr) by calendaring to produce radiopaque composite elastomers for protective clothings. The rubber mixts. were vulcanized and studied for mech. properties and X-ray absorption efficiency. The tensile strength of the vulcanizates were 15 and 5 MPa, resp., the elongation at break was higher than 300% in both cases. The lead equiv. of the natural rubber vulcanizates was 0,04-0,16 mm at 60 key and was by 33% higher than that for the Si rubber. The Bi(2)O(3) surface showed an electron donor nature and was more compatible with natural than with Si rubber.