The monomer reactivity ratios for radical copolymerizations of tributyltin methacrylate (monomer-1) with methyl methacrylate, propyl methacrylate and butyl methacrylate have been found as r1 = 0.79 and r2 = 1.0, r1 = 0.58 and r2 = 0.9, and r1 = 0.65 and r2 = 0.68 respectively.