Ascariasis is the most common helminthic infection, but the invasion of worms into the gallbladder is quite rare. This report illustrates the ultrasonographic findings in gallbladder ascariasis of a typical echogenic structure which exhibits nondirectional movements and contains a central anechoic tube, along the long axis of the gallbladder. The role of ultrasound as a diagnostic tool and in the follow-up treatment is stressed.