In a study of the parathyroid glands from 100 subjects who consecutively underwent autopsy, we found that median individual gland weight was 25.7 mg (95% weighed between 8.2 and 75.0 mg) and median individual gland parenchymal weight was 17.2 mg (95% weighed between 5.3 and 49.3 mg). Values were significantly skewed toward higher weights. Glandular weights were lower in patients with chronic illnesses, lower in women than in men, and lower in whites than in blacks. We found an inverse correlation between parenchymal weight and serum calcium concentration. Our results suggested that both total and parenchymal weights have a wider range of normal than is generally appreciated, and that a variety of factors probably affect parathyroid gland weight. A reevaluation of the weight of the parathyroid gland in normal persons is needed.