Some studies have suggested that premenopausal women show a decline in bone mass in function of age while other studies have not. Bone density in the spinal column and proximal femur (neck, Ward's triangle and trochanter) in 75 healthy white women between the ages of 30 and 49 without a history of irregular menstrual periods was correlated with age, weight, height and body mass. No statistically significant decline in bone density with age was seen during the premenopausal period. There was a positive correlation between bone density in the spine and proximal femur and weight and body mass indices. Our results suggest that healthy women do not show loss before menopause and it also seems that obesity has a favorable effect on these women's bone mass.