PURPOSE: To compare the clinical efficacy of iopamidol 370 and iopromide 370, as used in hepatic arteriography, in terms of their safety, patient tolerance, and image quality. MATERIALS AND METHODS: Between February and April 2001, 30 patients (M:F=27:3; mean age, 57 years) with hepatocellular carcinoma underwent hepatic angiography in which iopamidol 370 was used for transcatheter arterial chemoembolization (TAE). Sensations of heat or pain following contrast injection, a patient's distress or discomfort levels, and any side effects of the contrast media were monitored, and afterwards patients were asked whether they were aware of any differences between iopamidol 370 and iopromide 370, which had been used in hepatic angiography for previous TAE prior to February 2001. Three experienced independent radiologists assessed the diagnostic efficacy of the contrast media in terms of overall image quality, which was statistically analysed using Wilcoxon's signed ranks test. RESULTS: No patient experienced sensations of heat or pain during angiography, or showed any objective distress or discomfort, though two suffered mild nausea during angiography with iopamidol 370. None was aware of any difference between iopromide 370 and iopamidol 370. In terms of overall image quality, the diagnostic efficacy of contrast media in all patients was 'good'to 'excellent', with no significant difference between iopromide 370 and iopamidol 370 (p>0.05). CONCLUSION: In hepatic arteriography, the clinical efficacy of iopamidol 370 is comparable with that of another nonionic contrast medium, iopromide 370, in terms of safety, tolerance, and image quality. Iopamidol 370 is thus a useful alternative medium.