Metal on Metal joint replacements are considered as an alternative to Metal on Polyethylene implants, specially in case of young patients who require a safe and long-term performance of the device. The reduction of wear particles is a key factor in order to improve the life time of the implant in the human body. Metals have excellent properties that can increase the long-term success of the artificial joint replacement.However, corrosion of the metallic implant leads to an increase of the ion levels into the urine and blood of the patient. Metallic ions may produce a host response that can induce a catastrophic failure of the implant.The study of tribology and corrosion in biological environments (biotribocorrosion) will lead to a better understanding of the mechanisms that affect the degradation of the implant and the release of both particles and ions.The present paper reviews a number of medical results that show the increase of ions present in the body of patients. Different types of body response such as hypersensitivity and pseudotumours are also presented.The tribological performance of hip implants is explained as well as the corrosive behaviour of the most commonly used metallic materials. Biotribocorrosion studies are reviewed and the mechanisms of degradation of implants in biological environments are explained. Finally, some models of the performance of artificial joints are reported.