Biodegradable elastomeric poly(trimethylene carbonate) (PTMC) networks were efficiently formed by gamma irradiating the linear polymer in the presence of pentaerythritol triacrylate (PETA). The properties of networks formed upon irradiation of PTMC films containing (0.1.5 wt %.) PETA as cross-linking aid were evaluated. The gel contents and network densities increased with increasing PETA contents, irradiation dose, and initial polymer molecular weight. At a dose of 25 kGy, networks with gel fractions up to 0.96 could be obtained. The networks were noncytotoxic had elastic moduli below 10.7 MPa and high tensile strengths of up to 37.7 MPa. The incorporation of PETA also improved the resistance to creep and to tear propagation significantly, resulting in permanent set values that were as low as 0.9% strain and tear strengths up to 9.3 +/- 2.0 N/mm. Furthermore, the enzymatic erosion rates of the networks could be decreased from 12.0 +/- 2.9 to 3.0 +/- 1.6 mu m/day. These biodegradable elostomeric PTMC networks may be utilized in a broad range of medical applications.