Sixty six patients with primary gallbladder cancer were seen at the Hospital A. C. Camargo, São Paulo, Brazil, from January 1980 to December 1988 and who represent 0.14% of the total of 46,519 patients registered in the same period. Out of the 66 cases, 41 were submitted to an ultrasonographic exam. As to the other 25 patients, 20 had been submitted to a cholecystectomy at another hospital. This exam was not done in the other 5 patients for several reasons. The gallbladder cancer diagnosis was based on data obtained from surgery and confirmed by anatomopathological exam. Regarding the 20 cases operated on at another hospital there was a slide review performed at the Department of Pathologic Anatomy at the Hospital A. C. Camargo. The main ultrasonographic aspects in the 30 cases in which there was a correct diagnosis, were the following: solid mass in the gallbladder lumen in 13 cases (43.33%); solid tumour in the gallbladder area in 7 cases (23.33%); a tumour contiguous to the gallbladder reaching other organs in 6 cases (20.00%); an alteration of the gallbladder shape in 3 cases (10.00%) and an accentuated thickening of the gallbladder wall with inaccurate limits in one case (3.33%). In the sub-group in which the ultrasonographic exam was performed, cholelithiasis was observed in 31 (75.60%) of the 41 cases. There was a correct diagnosis in 18 (58.06%) of the 31 cases with cholelithiasis and in 8 (80.00%) of the 10 without cholelithiasis; not a significant difference. As to the ultrasonographic aspects of the false negative cases, in 9 (81.81%) of the 11 cases the images suggested cholelithiasis. Among these 9 cases there were 2 with an enlarged gallbladder, one case of escleroatrophic gallbladder and one case with thickened walls. The diagnosis of the other 2 cases were biliary mud in one and a probable cholelithiasis in another.