Exploration of the small common bile duct can be technically difficult and is associated with a significant risk of ductal injury or late stricture, or both. Transduodenal common duct exploration after sphincteroplasty (TCDE/S) is an alternative method of duct exploration that avoids choledochotomy. Cholecystectomy followed by TCDE/S was performed upon 28 patients with nondilated ducts and suspected choledocholithiasis. Common duct stones were retrieved in 17 patients. Failure to retrieve stones in the remaining 11 patients was attributed to either false-positive results of cholangiography, forceful passage of stones into the duodenum during the initial insertion of a Fogarty catheter through the cystic duct or a false-negative finding at duct exploration. There was no perioperative mortality. Two patients had asymptomatic postoperative hyperamylasemia. One patient had postoperative pancreatitis, hyperbilirubinemia and cholangitis that resolved with antibiotic therapy by the eighth postoperative day. Other complications included wound infection, delayed gastric emptying, pneumonia and otitis media. The over-all morbidity rate was 28.6 per cent. Long term follow-up was obtained in all 28 patients. All patients in the follow-up group are free of recurrent biliary tract disease. TCDE/S appears to be a safe and effective method of exploring the nondilated common bile duct.