A consecutive series of 108 common bile duct (CBD) explorations was studied to examine the efficacy of routine operative cholangiography and flexible choledochoscopy in the identification of choledocholithiasis. CBD exploration was performed according to the findings of routine operative cholangiography. Nine negative explorations were performed, only one of which would have been avoided had selective cholangiography been employed. Eight patients had unsuspected choledocholithiasis that would have been missed if selective operative cholangiography had been used. Flexible choledochoscopy identified CBD stones on 97 occasions; no additional retained stones were found on subsequent T tube cholangiography. In two cases stones were seen but could not be removed; immediate identification allowed planning for early removal. Flexible choledochoscopy is the most effective method of CBD exploration and should be used in all patients with suspected choledocholithiasis.