Ethyl-3-(acryloyloxy)methyloxetane (EAO), a monomer bearing an oxetane group in the side chain, was polymerized via ATRP using ethyl 2-bromoisobutyrate (EBIB) as initiator and CuBr as a catalyst complexed with 1,1,4,7,10,10-hexamethyltriethylenetetramine (HMTETA) as ligand. The polymer was characterized by H-1 NMR, FT-IR, GPC, and MALDI-TOF-MS. 1H NMR and FT-IR analyses revealed no ring opening of the oxetane group during polymerization.