Ultrasonographic scanning was performed in 39 patients who were clinically suspected of intrahepatic duct stone. Authors reviewed ultrasonographic features of intrahepatic duct stone in 33 cases confirmed by operation, percutaneous transhepatic cholangiography and/or computed tomography. RESULTS : 1. The sensitivity of ultrasonographic diagnosis in intrahepatic duct stone was 87%. 2. The distributionsof intrahepatic duct stone were intrahepatic only in 10 cases and intra- and extrahepatic in 23 cases. The most common location was both intraphepatic ducts in 18 cases, followed by left intrahepatic duct in 13 cases and right intraphepatic duct in 2 cases.3. Ultrasonographic findings were as follows : Nodular pattern is the most common, followed by mass, mixed, and linear or tubular impacted pattern in orders. Ductal dilatations were classified by 1) diffuse dilatation, 2) focal dilatation around stone, and 3) no dilataton around stone. Each patterns distribated egually for each. Acoustic shadowing was demonstrated in all patients except one. 4. In combined cases of echogenic materials with acoustic shadowing and ductal dilatation, intrahepatic duct stone could be easily indentified by ultrasonography.