It has been reported that bone density is increased in patients with treated hypoparathyroidism, though it is unclear whether this increase is attributable to the condition itself or to its treatment. We have recently investigated a 70 year old woman with untreated hypoparathyroidism from the time of thyroid surgery at the age of 29 years. Bone mineral content of the non-dominant distal forearm was 3.7 standard deviations above the mean normal value found in 23 healthy volunteers of comparable menopausal age, and was also above the mean normal value found in premenopausal women. The vertebral mineral density of her lumbar spine (measured by quantitative computed tomography) was 3.0 standard deviations above the mean normal value. These findings suggest that high bone density is a feature of hypoparathyroidism per se and that postmenopausal bone loss may be significantly attenuated in this condition.