Polymers having Fischer-type alkoxycarbenes in the side chain were synthesized by the reaction of pendant hydroxy groups with pentacarbonyltungsten acetoxyphenylcarbene [(CO)(5)W=C(Ph)O2CCH3, 2]. Namely, copolymers of methyl methacrylate with 4-hydroxybutyl methacrylate [poly(MMA-co-HBMA), 3b] were prepared and subjected to the reaction with 2 derived from tetramethylammonium salt of pentacarbonyltungsten hydroxyphenylcarbene [(CO)(5)W=C(Ph)ON(CH3)(4), 1] with acetyl chloride. Soluble copolymers (4b) with pendant metal-carbene segments were obtained, and H-1 NMR and UV spectroscopic analyses indicated that the metal-carbene moiety was introduced onto 20-70% of hydroxy groups of the copolymers. In contrast, the introduction of carbene moiety into a copolymer of MMA with 2-hydroxyethyl methacrylate [poly(MMA-co-HEMA), 3a] was unsuccessful because no reaction with 2 took place. The formed polymer (4b) served as a polymeric catalyst for the polymerization of phenylacetylene under the photo-irradiation.