Liver scintigraphy with 67-Ga citrate and alphafetoprotein (afp) determinations in the serum were carried out in 84 patients with liver mass lesions in the preceding sulphur colloid scans. Among these patients 51 cases were histologically verfied and 33 patients were regarded as clinically-proven cases. Scanning was carried out 72 hours after the intravenous injection of 3 mC 67-Ga-citrate. Corresponding to the intensity of 67-Ga uptake within the former liver lesions 3 groups of 67-Ga scans were differentiated: Ga 0 (the lesion showed no Ga uptake), Ga plus (the Ga uptake within the lesion was equal to that of the surrounding liver tissue) and Ga plus plus (the Ga uptake within the former lesion exceeded the physiological Ga uptake in the normal liver tissue). The number of cases, results of Ga scintigraphy and afp examinations as well as histological, clinical and nuclear medical diagnosis were correlated. It was shown that Ga plus plus cases were strongly suspect of hepatoma, whereas in Ga 0 cases a diagnosis of hepatoma could be excluded. In patients with Ga plus further investigations have to be performed (repeated afp examinations, angiography of the coeliac artery), because cirrhotic regeneration nodules, metastases and necrotic hepatomata were all found within this group. According to our experience liver scanning with 67Ga represents a useful auxiliary examination in liver diagnosis. Ga citrate scintigraphy of the liver is indicated in all cases with mass lesions detected by the routine sulphur colloid scan and in all patients in whom there is clinical suspicion of hepatoma, inorder to differentiate the origin of the lesions. In 2 cases of hepatoma marked Ga uptake was observed at a time when the afp was still negative.