Although the ultrasonography has been regarded as a main precedure in the diagnosis of bile duct and gallbladder diseases, a few reports concerning the ultrasonographic findings of biliary ascariasis appeared in the literature. Seven cases of real-time ultrasonographic diagnosis of biliary ascariasis were made in our hospital during last 15 months. In six, the diagnosis was confirmed by surgery or radiographic examination. The results were as follows : 1. The characteristic long, thick, highly reflective echo without distal acoustic shadowing in the extra-and/or intra-hepatic deucts were seen in all six proven cases. 2. The echogenic, nonshadowing images of the worms were seen as single stripe in five cases (containing a central, longitudinal, anechoic tube, suggesting its digestive tract in three cases) or multiple stripes in on case. But so-called coiled appearance or amorphous fragments wer not seen in our cases. 3. Associated findings were as follows : mild to moderate dilatation of the extrahepatic duct in all six proven cases, mild dilatation of the intrahepatic ducts in 3 cases, mild dilatation of the pancreatic duct in 1 case, intrahepatic stone in 1 case, contracted gallbladder containing single stone in 1 case and evidence of cholecystitis in 4 cases. 4. One false positive diagnosis of ascariasis in the gallbladder is considered due to reverberation artefact.