Five patients with early carcinoma of the gallbladder detected by ultrasonography were studied. Three complained of non-specific upper abdominal symptoms or were asymptomatic and two had severe biliary colic. Gallstones were present in the two patients without biliary symptoms. Early carcinoma of the gallbladder was demonstrated as a polypoid tumour by ultrasound in four patients and as thickening of the gallbladder wall in one. The tumour was over 2 cm in diameter in all but one patient in whom the tumour enlarged rapidly from 5 to 10 mm. Size of the tumour and extent of spread were closely related. All but one patient underwent curative resection. Ultrasonography enhances the detection of early carcinoma of the gallbladder especially in old patients with non-specific abdominal symptoms and the operative cure rate is thereby improved.