The atom transfer radical polymerization (ATRP) of (meth)acrylates from poly(dimethylsiloxane) (PDMS) macroinitiators is described. Hydrosilylation of commercially available difunctional hydrosilyl terminal PDMS (M-w/M-n > 1.3) with allyl- or 3-butenyl 2-bromoisobutyrate resulted in the macroinitiators. Linear semilogarithmic kinetic plots were obtained for the ATRP of acrylates and methacrylates. A nonlinear dependence of molecular weight on conversion was ascribed to a high concentration of low molecular weight chains not readily observed in the size exclusion chromatograph using THF as eluent. Well-defined monofunctional, low-polydispersity PDMS macroinitiators were synthesized by the anionic ring-opening polymerization of hexamethylcyclotrisiloxane. ATRP of acrylates and methacrylates from those compounds showed linear increases in Mn with conversion, demonstrating the effectiveness of ATRP to synthesize a variety of inorganic/organic polymer hybrids. A monofunctional poly(styrene-b-dimethylsiloxane) macroinitiator was used to initiate ATRP of n-butyl acrylate and methyl methacrylate, resulting in ABC organic/inorganic/organic hybrid triblock copolymers.