We report a case of non-insulin-dependent diabetes mellitus (NIDDM) co
mplicated with idiopathic hypoparathyroidism. A 74-year-old male was h
ospitalized because of diplopia, He was revealed to have NIDDM, The le
vels of serum Ca and intact-PTH were 6.3 mg/dl and < 5 pg/ml, respecti
vely, Brain computed tomography revealed abnormal calcification in the
cerebral basal ganglia and the cerebellum, After recovery from hypoca
lcemia, the endogenous insulin secretion was normalized, It is suggest
ed that the pathogenesis of NIDDM in this patient may have been relate
d to an insulin secretory defect as a result of hypocalcemia in additi
on to the hereditary risk.