A series of novel biodegradable unsaturated poly(ester amide)s (UPEAs) were synthesized through the solution polycondensation of two unsaturated monomers, di-p-nitrophenyl fumarate and L-phenylalanine 2-butene-1,4-diol diesterp-toluene sulfonate, and four other saturated monomers in different combinations. The UPEAs were obtained in fairly good yields with N,N-dimethylacetamide (DMA) as the solvent. The number-average and weight-average molecular weights of the UPEAs, measured by gel permeation chromatography, ranged from 10 to 30 kg/mol, they had a rather narrow molecular weight distribution of 1.40. The chemical structures of the novel biodegradable UPEAs were confirmed by both IR and NMR spectra. The UPEAs had higher glass-transition temperatures than saturated PEAS of similar structures, and their glass-transition temperatures were affected more by the C C double bond located in the diamide part than by those in the diester part. The solubility of the polymers was poor in water but better in DMA and dimethyl sulfoxide. With the availability of these inherent C C double bonds in the UPEA backbones, these UPEAs have the functionality of C C bonds, such as photochemical reactivity or the ability to react with or be modified by other bioactive or other environmentally sensitive compounds, and this can easily extend their applications to biomedical and pharmaceutical areas. (c) 2005 Wiley Periodicals, Inc.