Using Norland-Cameron Bone Mineral Analyzer BMA 178 Type, it has been found that bone mineral content of the radius is considerably less in male heavy smokers aged 61 to 75 and 76 to 90, then in nonsmokers with similar age. Less difference was found within the group of 61 to 75 year old women. Furthermore, also it has been pointed out that the sensitivity to calcitonin of rats inhaling tobacco smoke is considerably less, than that of control rats. It is possible that smoking promotes the decrease in mineral content of bones i.e. the aggravation of osteoporosis, by the means of calcitonin resistance. The authors recommend tobacco abstinence to patients with osteoporosis and to persons who are particularly endangered by osteoporosis (e.g. in menopause, in post-gastrectomic state ect.).