Hypoparathyroidism has not been reported in progressive systemic sclerosis (PSS). We describe a patient with PSS and polymyositis with clinical hypoparathyroidism in whom fibrosis of the parathyroid glands was found at autopsy. Normal parathyroid gland architecture includes a collagenous stroma which may fibrose due to the same etiologic factors that are responsible for fibrosis in other organs in PSS. Parathyroid involvement in PSS is probably more common than is currently appreciated.