The study dealing with the content of fluoride and calcium in stapedial bone and canal wall bone in otosclerosis was performed in 69 subjects (48 females and 21 males) out of the patients, in whom bone rebuilding activity had earlier been studied isotopically. The control group comprised 20 normal stapedies taken during autopsies. Fluoride content was determined by means of fluoride ions meter, the content of calcium was assessed by resorting to atomic absorptiometer. The content of studied elements was compared with the bone rebuilding activity and some clinical features such as the patient's age and duration of the disease. High fluoride content in otosclerotic stapes was revealed, being several times greater than in the bone of normal stapes. Concurrently the stapedial bone in otosclerosis contained less calcium as compared with the bone of normal stapes. In principle, that referred to otosclerotic focus and next to stapedial crura. The bones of stapedial footplates and otosclerotic foci with rebuilding activity lover han the means value had statistically significant, higher content of fluoride and calcium than the bones with greater rebuilding activity. Fluoride content in stapedial bone during otosclerosis dramatically increased with the patient's age and the length of the disease duration period, however, the calcium content had the tendency to decrease.