A new synthetic strategy for polymers containing amino acids in the main chain was developed. Monomers N-oxetanylalanine (N-Oxe-Ala-COOH), N-oxetanylglutamic acid (N-Oxe-Glu-COOH), and N-oxetanyllysine (N-Oxe-Lys-COOH) containing both oxetanyl and carboxyl groups were synthesized, and self-polyaddition and self-copolyaddition of these monomers afforded the corresponding polymers containing amino acids in the main chain [poly(OxAla), poly(OxLys), poly(OxGlu), poly(OxAla-co-OxGlu), poly(OxGlu-co-OxLys), and poly(OxAla-co-OxLys)] with molecular weight in the range of 9206620, in satisfactory yields. The physical properties, such as solubility, glass transition temperature, and thermal stability, were consistent with the amount of carboxyl groups at the chain ends. Biodegradability of the polymers was examined by the biochemical oxygen demand method; the decomposition ratios of poly(OxAla) and poly(OxAla-co-OxGlu) were about 60%, whereas that of poly(OxGlu) was nearly 100% after 28 days. (C) 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 50: 458-465, 2012