Late loss of initially integrated endosseous implants has generally been attributed to implant overload often the result of inappropriate prosthesis design. Implant placement is rarely contraindicated by preexisting systemic diseases, and no instances of medication-induced implant failure have been reported in the literature. This paper reports a case in which a patient lost five endosseous implants that had successfully osseointegrated and had been restored with a lower hybrid prosthesis approximately 6 months after diphosphonate therapy for osteoporosis was started. Keywords: diphosphonate, etidronate disodium, osseointegration, osteoporosis