Ultrasound angiography (USAG), sonographic imaging of the blood flow with intra-arterial infusion of carbon dioxide (CO2) microbubbles, was applied to pancreato-biliary lesions. Hypervascular pattern was observed in all cases of gallbladder elevated lesions except for debris balls. However, the vascular pattern of CO2 inflow that many arterial vessels were branching off into the lesion was characteristic for gallbladder carcinomas. The hemodynamics of solid tumors of the pancreas with USAG were divided into three patterns. Most of hypovascular nodules were duct cell carcinomas, while inflammatory pancreatic masses always exhibited isovascular except for two cases of hypovascular pattern. Furthermore, islet cell tumors showed hypervascular. In cases of mucin-producing cystic tumors of the pancreas, excrescent nodules or thickened septa within the lesions were identified as hypervascular. Other cystic tumors of the pancreas also presented peculiar hemodynamics. Therefore USAG is potentially useful for detecting various vascular patterns of pancreato-biliary lesions, contributory as a diagnostic tool in this area.