A composite was synthesized by irradiation of poly(butylene succinate) (PBS) and glass fiber (GF) in the presence of a polyfunctional monomer, trimethallyl isocyanurate (TMAIC), which accelerates gel formation of the matrix (PBS) in the composite. The highest gel fraction was achieved at 1% concentration of TMAIC at the dose level of 200 kGy compared to other concentrations. Mechanical properties of the composites were highly dependent on the gel fraction of the polymer and volume fraction of glass fiber reinforcement in the composite. Optimal conditions to synthesize a PBS/GF composite reaching maximum value of bending strength were 1% TMAIC, 67% fiber volume fraction, and irradiation dose of 200 kGy. These synthesized PBS/GF composites can be degraded by enzymes produced from the microorganism population in soil. (C) 2003 Wiley Periodicals, Inc.