Studies were undertaken in 40 patients with chronic pancreatitis six months to seven and a half years (mean 25 months) after operation, results being compared with pre-operative findings. Measurements included: exercise capacity, absence of pain, body weight, endocrine (36) and exocrine (25) pancreatic function. Almost all patients returned to full or only slightly impaired activity, were free of pain or had less pain and weight increase. Exocrine pancreatic function (secretin-pancreozymin test and faecal fat) was noted in 11 of 25 patients. In another 11 pre-operative progression was arrested. But endocrine function improved in only three of 36 and worsened in 13 (manifestation of subclinical diabetes in eight, worse glucose tolerance in five). The results justify a more active surgical approach in the treatment of chronic pancreatitis in order to save the patients from an often long and painful "burning out" of the disease on purely conservative treatment. Furthermore, exocrine pancreatic function, at least, is maintained or improved.