With an advent of cholangiofiberscope in 1975, tremendous changes have been made in thinking way on the treatment of biliary tract stones. The technique of percutaneous transhepatic cholangioscopy (PTCS) was detailed and its clinical significance was discussed in this paper. PTCS is the technique which is conducted by insertion of cholangiofiberscope into the biliary tract through the dilated fistula produced by percutaneous transhepatic biliary drainage (PTBD). Advantages of this techniques are; (1) it is applicable to the cases who had had bilio-enteric anastomosis or gastro-jejunostomy before, (2) it can be repeatedly carried out if the fistula is maintained open, (3) stones visible are readily removable with the instruments guided by cholangiofiberscope and finally, (4) the informations necessary to select an adequate surgical procedure can be obtained by PTCS, because biliary architecture is clearly delineated. For the period of 18 years started from 1975, 126 cases with intrahepatic stones have been encountered in our Hospital, endoscopic stones extraction technique was successful in 106 out of 121 cases excluding 5 cases converted for hepatic lobectomy. And the prognosis of the cases in which stones were successfully extracted were, in general, good. Therefore, the authors believe that the therapeutic results would be significantly improved with the routine use of PTCS.