To assess the contribution of parenchymal hypertension to pain, pancreatic tissue pressures were measured intraoperatively in 17 patients with chronic pancreatitis and in four other patients undergoing pancreatic surgery (reference group). The technique involved direct fine needle cannulation of the pancreas using a flow infusion system, which measured parenchymal resistance to this infusion. Three to six recordings were obtained at each site. In chronic pancreatitis the pressure (mean +/- s.e.m.) was substantially elevated in all regions of the pancreas compared with reference subjects: head (257 +/- 59 versus 19 +/- 5 mmHg, P less than 0.05); body (201 +/- 51 versus 13 +/- 6 mmHg, P less than 0.05) and tail (161 +/- 45 versus 11 +/- 3 mmHg, P less than 0.05). Elevation was greater in areas of calcific disease (281-383 mmHg) than in non-calcific disease (81-120 mmHg, P less than 0.05). Mean pancreatic ductal pressure in 10 patients (seven with calcific disease) was 20 +/- 4 mmHg. Differential pressure measurements within the pancreas helped determine the extent of resection in six patients with diffuse disease. The greatly increased tissue pressures in chronic pancreatitis, especially in the presence of calcification, suggest a possible 'compartment syndrome'.