The synthesis of poly(tetrahydrofuran (THF)) having 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) moiety at the chain end and its application as a polymeric counter radical to the living radical polymerization of styrene were performed. The TEMPO moiety could be introduced in quantitative efficiency by the reaction of living poly(THF) initiated by methyl trifluoromethanesulfonate with sodium 4-oxy-TEMPO. The resulting polymer could serve as a polymeric counter radical in the radical polymerization of styrene with benzoyl peroxide to give the corresponding block copolymer quantitatively. Furthermore, it was found that this radical polymerization proceeded in accordance with a living mechanism because the molecular weight of the block copolymer linearly increased with increasing conversion of styrene and was inversely proportional to the initial concentration of poly(THF).