Operations upon the biliary tract and sphincter of Oddi have not proved to be effective in the treatment of chronic pancreatitis not associated with gallstones. Howard and Jordan3 reported 69% recurrence in 16 such patients within five years of cholecystectomy and sphincterotomy. We have observed failure of sphincterotomy alone to protect against progression of the disease in 39% of 18 similar patients within one year of the operation. A characteristic common to most of the patients in this group is a grossly distorted main pancreatic duct with multiple areas of dilatation and stenosis. Without entering into the controversy concerning the etiologic implications of this observation, it is readily apparent that a procedure designed to relieve obstruction at one end or the other of the pancreatic duct will not suffice to drain adequately the entire duct in this situation. For this reason the procedure of lateral drainage of almost the