Infection with the liver fluke, Opisthorchis viverrini (Ov), is an important public health problem in northeast Thailand where people have a habit of eating raw or inadequately cooked fish. Opisthorchiasis is associated with a number of asymptomatic hepatobiliary abnormalities and cholangiocarcinoma (CCA) that can be observed conveniently by ultrasonography. Based on our accumulated data, characteristic features of ultrasonographic findings of hepatobiliary pathology in Ov infection are reviewed. Also, the ultrasonographic classification of periductal fibrosis in Ov infection of opisthorchiasis will be proposed herein.