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Otosclerosis is a bonydyscrasia of the otic capsule. In its active phase it is characterized byhisto-pathologic findings of osteoclast production. The new investigative fieldof osteoclastogenesis (osteoclast production) has evolved giving rise to anunderstanding of the pathogenesis of otosclerosis. A simple cartoon ofosteoclastogenesis will be diagramed as applied to bone, the normal oticcapsule and to otosclerosis. Basic science researchin the experimental animal otic capsule has given insight into the process ofevolution of otosclerosis. The normal otic capsule is preserved with verylittle bone turnover as result of the production of a cytokine by themembranous inner ear that prevents the activation of osteoclasts. Furtherresearch in animals that are genetically unable to produce this cytokine showedthe production of hearing loss and histopathology of the temporal bonesconsistent with that seen in otosclerosis. The active phase of otosclerosis ischar-acterized by the activation of osteoclasts suggested by some form ofinflammation. The measles virus has been implicated in some instances ofotosclerosis. Applying theunderstanding of osteo-clastogenesis to the treatment of otosclerosis has led tothe clinical use of the class of drugs called bisphosphonates. Thebisphosphonate group of drugs specifically targets osteoclasts by reducingproduction of osteoclasts and accelerating early cell death of osteoclasts. Before the advent ofnewer drugs fluoride was the only medical treatment for otosclerosis. Thisrecent basic science research leads to an understanding of the rationale forthe use of the class of bisphosphonates in the medical treatment ofotosclerosis. Osteoclastogenesis, itsrole in the production of otosclerosis and the rationale for use ofbisphosphonates will be explained. The balance of inciting and blockingcytokines in osteoclast production explains the normal otic capsule.Bisphosphonate management will be detailed in case histories of patients whohad previously undergone stapedectomy and long after the postoperative perioddeveloped hearing loss. The cases will illustrate the treatment algorithms with bisphosphonates and the response to treatment.