The results of direct decompression of the common duct for malignant obstruction of the distal biliary tree by side-to-side choledochoduodenostomy are presented. Thirty-three patients were treated with twenty-four (73 per cent) having carcinoma of the pancreas. Seventy-two per cent of the patients had had previous cholecystectomy or cholelithiasis whereas the common duct was utilized in preference to cholecystojejunostomy in six patients. The operative mortality was 12 per cent and six patients had complications. No deaths could be attributed to the choledochoduodenostomy, and complications did not significantly affect palliation. Mean postoperative survival was 10 +/- 0.9 months. Two patients had obstruction of the anastomosis as a terminal event. This study suggests that appropriately applied choledochoduodenostomy is a simple, effective means to decompress the common duct obstructed by tumor.