Abstract: Menopause is one of the most important accelerating factors of bone loss in women. This study was designed to evaluate the effects of the age of menopause on BMD in Iranian women. The women referred for Bone Densitometry who were menopaused and did not have hysterectomy before their menopause were selected as every consecutive patient. Those who had any other risk factor for osteoporosis were excluded. The patients were divided into four groups according to their age of menopause, and BMD was measured by Dual Energy X-rays Absorptiometry (DEXA) on the lumbar spine (L1-L4) and the upper extremity of the femur. The mean BMD of both regions for each group was calculated and compared with the mean BMD of a group of normal Iranian women with Chi square test and the mean difference was determined. The results were as follows: L1-L4 _Femoral Neck_______ Menopausal age No. Mean dif.% SD SEM No. Mean dif.% SD SEM Total _ 716 -3. 1.1 0.04 691 -3.6 2.1 0.08 Group 1 < 40 52 -7.4 1.1 0.15 50 -8 5 0.71 Group 2 40-49 288 -6.7 2.4 0.14 277 -5.9 4 0.24 Group 3 50-54 295 -1.1 7.9 0.46 286 -0.9 1.5 0.09 Group 4 > 54 81 0.2 4.7 0.52 78 0.4 2.2 0.26 This study shows that the mean BMD of the menopaused women is lower than the normal mean BMD of the same age, but it correlates with the age of menopause. There is no difference when the menopause occurs between the age of 50-54 (Normal age of menopause in Iran: 50-54?!). Menopause before this period is with a lower and after that is with a higher BMD compared to the normal group. The effect of the age of menopause on the BMD of both the trabecular and the compact bone was the same.