Since 1971, in Glasgow Royal Infirmary 880 patients with acute pancreatitis (AP) have been prospectively studied. Only two (0.23 per cent) have been found with associated hyperparathyroidism (HPT), one of whom also had gallstones. During the period of study daily serum calcium levels were measured routinely in all patients with AP and, in addition, a consecutive series of 200 patients had daily mineral metabolism screening of blood and urine in an attempt to identify patients with hypercalcaemia as an aetiological factor. A separate group of 90 patients had sequential daily serum calcium and parathyroid hormone assays (PTH) performed for the first five days of their hospital admission and one of the patients described in this paper came from this group. She is the first patient, to our knowledge, documented in this manner. The overall pattern of the PTH and calcium response from all these patients is also recorded according to the severity of the AP. Hyperparathyroidism is uncommonly associated with AP and when it is other aetiological factors must be excluded.