A retrospective analysis of 49 patients with 55 liver abscesses evaluated by diagnostic ultrasonography was made. The sonographic appearances were varied and non-specific. 96% of the abscesses were in the right lobe of the liver. Sonographic features which were frequently observed include (a) predominantly hypoechoic internal echotexture (64%) (b) distal sonic enhancement (98%) (c) well-defined margin with an abrupt transition between normal liver parenchyma and lesion (96%) and (d) absence of wall echoes (89%). A combination of these features has considerable diagnostic value. Distal sonic enhancement is of particular diagnostic importance. In equivocal cases the diagnosis can be quickly determined by percutaneous needle aspiration under ultrasound guidance.