Injection molded tensile bars composed of native corn starch (0-70%), poly(d,l-lactic acid) (95% L) (PLA, 13-100%) and poly(hydroxyester-ether) (PHEE, 0-27%) were buried in soil for 1 year in order to study the effects of starch and PHEE on rates of biodegradation. Rates of weight loss increased in the order pure PLA (~0%/year)<starch/PLA (0-15%/year)<starch/PHEE/ PLA (4-50%/year) and increased with increasing starch and PHEE contents. Weight losses were due to starch only with the degradation proceeding from outside to inside along a narrow zone. Tensile strength did not change with time for pure PLA and, after an initial decline, did not change much for the other compositions. Some formulations containing PHEE and lower (40%) starch levels had higher tensile strengths after initial exposure to soil than those without PHEE.