Biodegradation or bioresorption of implant materials is characterized by changes in the physicochemical properties of the material after implantation. In the case of calcium phosphate (CaP) ceramic implants, physical changes may include disintegration, loss of mechanical strength, and changes in porosity; chemical changes may include dissolution, formation of other CaP phases, and possible transformation of these phases (from one type of CaP to another) on the ceramic surfaces. Many reports in the literature on the biodegradation or bioresorption of CaP ceramics cannot be taken seriously because of the lack of appropriate characterization of the material, that is, whether it is pure calcium hydroxyapatite (HA), which has the formula Ca,,(PO,),(OH),; pure whitlockite, which is also named p-tricalcium phosphate (p-TCP), and which has the formula Ca,(PO,),; or a biphasic (BCP), which is some mixture of P-TCP and HA, the ratio of p-TCP to HA for which is not always defined. Thus, for this report, which is based on the collective scientific experience of the task group and on the scientific literature, the materials that have been appropriately characterized by X-ray diffraction were considered. These materials are sintered HA; aand P-TCP; BCP; and hydrothermally converted CaCO, (also known as corralline HA). The questions addressed were the following: 1) Do these materials biodegrade? 2) What are the factors affecting biodegradation-bioresorption? 3) What are the possible mechanisms of biodegradation-bioresorption? 4) What are the methods used for the in vitro and in vivo assessment of biodegradation-bioresorption? 5 ) What factors should be considered in the biodegradation of CaP ceramics in special cases (for example, as coatings on metals or as components of polymer4eramic composites)? This report is presented with the following components: 1) answers to the questions addressed; 2) implications of biodegradation-bioresorption; 3) recommendations for future studies and for putting unsubstantiated beliefs and myths to rest.