Novel water-soluble unsaturated poly(ether amide)s (PEAs) were synthesized by low-temperature polycondensation of fumaryl chloride and amine-terminated poly(ethylene glycol) (Jeffamine(R)). The unsaturated copolymers were further chemically modified with thiols to provide reactive pendant functional groups. Hydrogels based on these copolymers were prepared by copolymerization of the PEA with N-vinyl pyrrolidone exposure to ultraviolet (UV) irradiation. The resulting hydrogels exhibited a high swelling ratio, and the magnitude of swelling depended on the molecular weight of Jeffamine(R). The swelling ratio and equilibrium water content tended to increase with increasing chain length of the Jeffamine(R) used in copolymer synthesis.