Acute haemorrhagic and/or necrotizing pancreatitis is a most serious condition. A retrospective account is presented of the clinical course, treatment and results in 61 patients with the diagnosis confirmed at laparotomy and/or autopsy. Forty-eight patients (79%) died while in hospital. Of the 13 surviving patients, 10 were followed up for periods ranging from 1.5 to 9 years. They were reinvestigated with respect to morphologic and exocrine and endocrine functional changes in the pancreas. The aetiology of the acute condition was biliary tract disease in 33% of the total series and alcoholism in 59%. Neither cause of the disease nor type of treatment (surgery with or without peritoneal lavage) had statistically significant effect on survival. At the follow-up examination the endocrine and exocrine pancreatic functions were satisfactory in many patients. In almost half of the surviving patients, endoscopic retrograde pancreatography showed openly minor changes.