BACKGROUND: Although the mean weight of normal parathyroid glands is known, reports concerning the weight of hyperplastic glands in renal hyperparathyroidism are rare. The aim was to collect data about the weight of such glands and also to study the intraindividual distribution. METHODS: Statistical results are presented about the weight of 60 parathyroid glands that were removed in 20 patients with renal hyperparathyroidism (the fourth gland was subtotally removed and therefore not included in the study). RESULTS: The median weight was 1.005 g, with a range from 0.10 to 7.15 g. All removed glands were enlarged, but the most salient finding was the wide distribution of weights. Also, the intra-individual variation was great. The largest gland of each patient weighed, on average, three to four times more than the smallest gland of the same subject. CONCLUSION: The weight of the superior glands tended to be somewhat greater in comparison with the inferior glands.