There is an increasing need for synthetic bone substitute materials that decrease the need for allografts and autografts. In this study, composites of β-tricalcium phosphate and a biodegradable poly(L-lactide-co--caprolactone) were manufactured using extrusion to form biodegradable composites with high β-tricalcium phosphate contents for osteoconductivity. The hydrolytic degradation of the composites containing 0, 10, 20, 35 and 50% of β-tricalcium phosphate was studied in vitro for 52 weeks. During the study, it was observed that β-tricalcium phosphate did not have an effect on the degradation rate of the polymer matrix. However, the crystallinity of the materials increased throughout the test series and changes in glass transition temperatures were also observed as the comonomer ratio of the polymer matrix changed as the degradation proceeded. The results show that the materials have desirable degradation properties and, thus, possess great potential as bioabsorbable and osteoconductive bone filling materials.