Anionic polymerizations of 3-(trimethoxysilyl)propyl (3a), 3-(triethoxysilyl)propyl (3b), and 3-(tri-2-propoxysilyl)propyl methacrylates (3c) were investigated in THF at -78-degrees-C with a variety of initiators. They included butyllithium, 1,1-diphenylhexyllithium, 1,1-diphenylhexyllithium-LiCl, cumylpotassium capped with 1,1-diphenylethylene (DPE), 1,4-dipotassio-1,1,4,4-tetraphenylbutane from potassium naphthalenide and DPE, benzylmagnesium chloride, potassium tert-butoxide, and LiAlH4. The polymerization of 3c proceeded well to give poly(3c) quantitatively with each of all the initiators except for LiAlH4. Among these, the combination of 1,1-diphenylhexyllithium and LiCl is particularly an excellent initiator system which produces polymers of predictable molecular weights and of very narrow molecular weight distributions (M(w)BAR/M(n)BAR < 1.05). Thus, the living character of the polymerization of 3c with this system has been demonstrated. A novel well-defined block copolymer, poly(3c-b-methyl methacrylate), could be synthesized by the sequential anionic living polymerization of 3c with methyl methacrylate. Similarly, block copolymers of poly(methyl methacrylate-b-3c) and poly(styrene-b-3c) were also synthesized quantitatively. The hydrolytic behavior of poly(3c) was studied in detail in water, 2 N HCl, or 1 N NaOH.