A new enzyme modification has been devised where various vinyl monomers were graft-polymerized using enzyme-containing aliphatic azo groups as initiators. Thus, an enzyme, lipase, which is not soluble in organic solvents, was made soluble in organic solvents. The modified enzyme catalyzed the esterification reaction in chloroform. Catalytic activity in chloroform was obtained by modification with amphiphilic polymers, such as poly(N-vinylpyrrolidone), as well as hydrophobic polymers, such as polystyrene and poly(methyl methacrylate). The catalytic activities of the hybrid enzymes increased linearly with increased solubility in chloroform. The hybrid enzymes were thermally stable and used repeatedly.