Twenty-five patients with histologically proven cancer of the liver were studied with liver scintiphotography using Ga67 citrate. Of 25 cases, 5 (4 hepatomas, 1 metastatic cancer) showed increased uptake of Ga67 citrate in the tumor, 8 (3 hepatomas, 1 cholangioma, 4 metastatic cancers) showed equilibrated uptake, 6 (all metastatic cancers) showed decreased uptake, and the remaining 6 (2 hepatomas, 4 metastatic cancers) showed undetermined uptake. Of the cases in which Ga67 citrate in the tumor showed poor uptake, 3 had accepted effective treatment of the lesions prior to the study. In 22 of 25 cases, the vascularity of the tumors was investigated by selective hepatic arteriography. There was a positive correlation between visualization of the lesion with Ga67 citrate and vascularity within the tumor. The presence of the tumors in the liver was confirmed in 52 per cent of 25 cases with Ga67 citrate scintiphotography alone, 70 per cent of 24 cases with Au198 colloid scintiphotography alone, 72 per cent of 25 cases with both Ga67 citrate and Au198 colloid scintiphotography, 81 per cent of 22 cases with hepatic arteriography alone, and 92 per cent of 25 cases with both scintiphotography and arteriography. Ga67 citrate scintiphotography combined with the Au198 colloid study can be regarded as a fairly useful diagnostic procedure in evaluation of liver cancer, as well as a valuable index to follow the effect of various treatments on the tumor.