Two types of new composite implant materials are investigated. Their mechanical characteristics and biocompatibility are determined. The first type of the biomaterials is based on silicate glass (SG) and hydroxyapatite. Both the natural (NHAp) and a synthetic (HAp) hydroxyapatites were used. The second type of the biomaterials was made of an ultrahigh-molecular polyethylene (UHMPE) and the NHAp. Composite materials of both the types were implanted into the rabbit femur. The bond strength between the bone tissue and the implants was determined in 2, 4, 10, and 25 weeks. The stress–strain state of bone–implant system was determined by the finite element method (FEM).