Several acrylic copolymers containing, at random, sequences of poly(ethyl acrylate) and poly(N-(2-hydroxyethyl)acrylamide) were obtained from ethyl acrylate as the only monomer starting material in a chain polymerization process, catalyzed by Candida antarctica lipase B. In the presence of ethanolamine, the enzyme not only catalyzes the chain polymerization of ethyl acrylate but also aminolysis the pendant ester groups. The products, characterized by FTIR, 1 H and 13 C NMR and UV-MALDI-TOF-MS, show low molecular weight and high monodispersity. The activity showed by C. antarctica lipase B in the polymerization reaction is a new example of enzyme promiscuity.