Pathogenesis, diagnosis, predicting severity, and treatment of acute biliary pancreatitis are reviewed. Clinical characteristics, treatment and outcome were investigated in 23 patients with severe, acute biliary pancreatitis. Conservative treatment is successful in most of patients with acute biliary pancreatitis. Surgical treatment for biliary stones should be followed by an initial conservative treatment. However, in patients with severe pancreatitis, who has poor prognosis, intensive care is necessary and surgical treatment must be adequately performed, in failure of active medical treatments. In these cases, the timing of operation is important. When biliary lesions, acute septic cholangitis or impacted ampullary stones, are responsible for the severe condition, and can't be treated by a medical procedure, such as PTCD or EST, surgical treatment of the biliary tract should be considered.