Liver angiography and liver perfusion scintigraphy with Tc-99m-labeled macroaggregated albumin (MAA) were performed in 36 patients with liver metastases from colorectal cancer prior to continuous 5-fluorouracil hepatic artery infusion (HAI) hemotherapy. Of the 26 patients showing metastases on arteriogram, five revealed increased tumor vascularisation, five had normal vascularisation, and 16 showed decreased vascularisation of the metastases relative to liver. In liver perfusion scintigraphy, 15 of the 36 patients showed increased perfusion of the metastases, four had normal perfusion, and 17 had decreased tumor perfusion. The observed differences in survival in the different groups were not statistically significant: patients survived 15 months in the group with increased tumor vascularisation, 8 months for normal vascularisation, and 14 months for decreased tumor vascularisation; survival was 28 months for the group of increased, and 13 and 14 months for the normal and decreased tumor perfusion groups respectively. Also, response rates with 80%, 40%, and 75% responders in the group of increased, normal, and decreased tumor vascularisation, respectively, and 80%, 50%, and 59% responders in the group of increased, normal, and decreased perfusion, respectively, were not significantly different. These results indicate that there is no possibility to discriminate potential responders from nonresponders by results of liver angiography or perfusion scintigraphy.