Present research is concerned with polymerization of various monomers on the surface of different clays. The monomers used were methyl methacrylate, vinyl chloride, acrylonitrile and N,N-dimethylaminoethyl methacrylate. The clays investigated were halloysite, bentonite, diatomaceous earth. A talc sample was also investigated for comparison. The clay surfaces were activated by acid treatment (50% H₂SO₄) and drying at 120℃ under vacuum, and the samples were subjected to one of the following three polymerization processes; 1)direct single step polymerization in which activated clay was dispersed directly into a polymerization mixture with an initiator such as AIBN and benzoyl peroxide, 2)redox polymerization in which N,N-dimethyl toluidine (or aniline) was adsorbed on the clay prior to the polymerization of monomers with a peroxide, and 3)solution polymerization in which solvents such as benzene, n-hexane and n-heptane were used as diluents, otherwise same to the above procedures. The observations we have made are as follows: i)Acid treatment activates and acidifies clay surface such that it improves polymerization yield as well as the amount of tightly bound polymers. ii)In solution polymerization the rate of polymerization dropped generally. When benzoyl peroxide was used as an initiator the best rate was observed in benzene compared with other solvent such as n-hexane. iii)Redox polymerization with N,N-dimethylaniline or copolymerization with monomer N,N-dimethylaminoethyl methacrylate with benzoyl peroxid as catalysts improved the polymer adhesion to the clay. iv)Polymer-coated clay containing around 8% of polymer did not sediment in water for prolonged time period (one month). v)Acrylonitrile failed to polymerize well on clay surface. vi)Talc was found to be more active in polymerization than clays. However the portion of bound polymer was small.