Ultrasongraphy has proven useful in evaluating the diagnosis of many hepatobiliary diseases. But a few reports about the ultrasonographic findings of biliary ascariasis appeared in the literature. Sonographic diagnosis of biliary ascariasis in the common bile duct was made in 2 patients, and was confirmed by endoscopic visualization and retrograde cholangiography. Ultrasonographic procedure of the removed worm was also performed in the water bath. The results was as follows: 1) In case 1, Ultrasonogram showed spaghetti apperance of 2 overlapping longitudinal interfaces without acoustic shadow in the logitudinal scanning of the common bile duct(spaghetti sign) and bull's eye echo pattern of annular hyperechoic configuration in the horizontal scanning of the common bile duct(bull's eye appearance). 2) In case 2, Ultrasonogram showed inner tube appearance of hyperechoic parallel stripes containing a central longitudinal anechoic tube(inner tube sign) and a hyperechoic strip without an inner tube(strip sign) in the longitudinal scanning of the common bile duct. Bull's eye appearance was also showed in the horizontal scanning of the common bile duct. 3) As for ultrasonographic configuration of ascaris lumbricoides, performed in the water bath, we got three aspects. In the longitudinal scanning, it showed hyperechoic parallel stripes containing a central anechic tube, probably representing its digestive tract, on the vertical sonobeam(inner tube sign) and hyperechoic string on the non-ventical sonobeam(strip sign). In the horizontal scanning, it showed annular hyperechoic configuration(bull's eye apperance). We now believe that ultrasonography, being safe, quick and noninvasive, should be the first imaging method for suspected biliary ascariasis.