105 patients with intractable pain due to chronic pancreatitis were selected for treatment by lateral pancreatico-jejunostomy (according to the procedure of Partington Rochelle) after pre operative endoscopy had revealed a dilatation of the main pancreatic duct (mean : 6 mm). Pancreatico-jejunostomy was the unique procedure in 59 patients; it was associated with a biliary or duodenal diversion in 46 others patients. 2 patients died post-operatively and 12 required a second operation some years subsequent to the pancreatic drainage, for biliary stenosis due to the progress of the sclerosis. 8 of the 22 late death were in direct relation with the persistence of alcohol intake and 4 others died from an extra pancreatic cancer. Peptic ulcer complicating pancreatico-jejunostomy appeared in three patients and two of them died from hemorrhage. Mean observation time was 65 years. Long term results were excellent or improved in 93.4% what pain relief concern, but the progression of exocrine or endocrine pancreatic insufficiency indicates that decompression of the dilated pancreatic duct does not prevent continuing destruction of pancreatic glandular tissue. In spite of these good results, the rational for duct drainage as a mean to decrease the intraductal pressure secondary to stricture is unclear. Neither the patency of the anastomosis, nor the presence or not of pancreatic lithiasis or the size of the dilated pancreatic duct seem to be crucial for pain relief after pancreatico-jejunostomy. Notwithstanding of the dubiousness of the mechanism of action of the drainage procedure, pancreato-jejunostomy remains the most effective procedure for relief of pain in chronic pancreatitis with dilated duct.