Abstract: A process of incorporating non-polymeric particulate matter such as magnetic materials, pigments and minerals, into a cross-linked styrene-based polymeric matrix, which process comprises dispersing the non-polymeric particles with a polymeric dispersant in a medium containing one or more vinyl monomers and a crosslinking agent, and adding a polymerization initiator. Typical polymeric dispersants are copolymers, styrenes and tertiary-nitrogen-containing vinyl monomers. Non-polymeric particulate matter incorporated into polymeric beads by this process is resistant to chemical attack and the beads may be used to prepare composite adsorbents or ion exchange resins.