Purpose: To observe the trabecular and cortical bone mineral density values of a normal Turkish population, to examine the effect of age in males, and age and duration of menopause in a female population on bone mineral density. Also to compare Turkish population bone mineral density values with the reference values in developed countries. Materials and methods: Trabecular and cortical bone mineral densities were measured by the quantitative CT method in 255 (110 male and 145 female) normal cases. Results: According to the linear regression test results, loss of bone mineral density per year was 1.97 mg/ml and 2.09 mg/ml for females and 1.37 mg/ml and 1.04 mg/ml for males in the trabecular and cortical bone compartments, respectively. A 70-year-old female loses 56.7% and 31.3% of the bone mass at 20 years of age for the trabecular and cortical compartments, respectively. These ratios were 41% and 16.1% for the male population. Most loss in bone mass was observed in the premenopausal and early postmenopausal period. In the postmenopausal period, duration of menopause had more effect on bone mass than age. Loss of trabecular bone mass per year in the postmenopausal period was 2.36 mg/ml and 2.84 mg/ml with respect to age and duration of menopause, respectively. Conclusions: Quantitative CT is a valuable method to determine bone mass because it allows to detect bone mass of trabecular and cortical bone separately. Loss in trabecular bone was found to be higher than in cortical bone for both sexes, while overall bone loss was higher in females. Rate of loss increases in the menopause period. Duration of menopause had more effect on bone mass than age. Bone mineral density values in Turkey were similar to reference values of western countries.