PURPOSE: To assess the benefit and the effect of intraarterial lipiodol application on histological analysis of patients suspected of having HCC. To determine whether lipiodol marking leads to a better biopsy result and how lipiodol or a transarterial chemoembolization influences the histological diagnosis. MATERIALS AND METHODS: Two groups of patients were examined. Group A included 14 patients highly suspected of having an HCC which had previously been unsuccessfully biopsied. A transarterial embolization with lipiodol was performed in these patients to mark intrahepatic tumors which could not otherwise be defined in unenhanced CT. A biopsy was then repeated. Group B included 22 patients undergoing therapy using transarterial chemoembolization (TACE). A biopsy was performed to support the diagnosis of a multifocal HCC before changing the therapy. RESULTS: The transversal diameters of the biopsied tumors were similar in both groups (A: 22 mm; B: 21 mm). The length of percutaneous access was 71 mm in Group A and 88 mm in Group B. In eleven of 14 patients of Group A we confirmed the diagnosis of an HCC. Thirty-six procedures were necessary for this confirmation. In Group B we confirmed the diagnosis in 17 of 22 patients. In addition, we found typical histological modification due to hepatic cirrhosis and virus hepatitis. Lipiodol had no negative influence on the histological diagnosis. CONCLUSION: Applying lipiodol for marking and delineating HCC-suspicious liver tumors in cases of formerly negative histology seems to enhance the success of biopsy, confirming the diagnosis of an HCC