This clinical report describes an unusual consequence of peri-implantitis and subsequent implant failure in a 72-year-old man. Following uneventful implant removal, osteomyelitis developed at the implant site, which subsequently weakened the mandible sufficiently for a pathological fracture to occur. The patient was treated successfully by use of an intensive oral hygiene regime, antibiotics, and conservative management. The consequences and management of implant failure are discussed, as well as issues relating to the management of osteomyelitis and pathological bone fracture.