This study investigates the influence of silanisation on the mechanical and degradation behaviour of PLGA/HA composites. Three different silanes (mercaptopropyl trimethoxy silane (MPTMS), aminopropyl trimethoxy silane (APTMS) and aminopropyltriethoxy silane (APTES)) were applied to HA substrates in order to study the effect of head group (which binds to the polymer) and tail group (which binds to the surface hydroxyl groups in HA). A composite of hydroxyapatite (HA) and poly(d,l lactide-co-glycolide (50:50)) (PLGA) was investigated. The influence of concentration, the reaction time, drying temperature and substrate surface on silanisation was examined. TGA was used to detect the degree of silanisation. HA with MPTMS (1wt.% MPTMS with reaction time of 1h) was used as filler in PLGA-30wt.% HA composites for an in-vitro degradation study carried out in PBS. In addition, the mechanical properties of the composites were studied. Silanisation affects the properties of the composite by improving the bonding at the interface and hence it was found to influence the plastic mechanical properties rather than the elastic mechanical properties or the degradation profile of the composite.