Careful staging of hepatic tumors forms the basis of appropriate selection of, and is a precondition for, customized treatment. Advances in radiodiagnostic technology have increased the sensitivity of noninvasive liver staging by means of magnetic resonance imaging (MRI), computed tomography (CT), and helical CT (HCT). Nevertheless, surgical exploration and intraoperative ultrasonography (IOUS) are considered the "gold standard." The value of HCT and IOUS was investigated in patients who underwent orthotopic liver transplantation (OLT) (group A; n=23) or hepatic resection for hepatocellular carcinoma (HCC) (group B; n=52). In group A, the results of liver imaging (HCT performed immediately before OLT, IOUS) were compared with histopathological results after 3-mm slicing of the explanted liver. In group B, patients were evaluated by CT (n=8), HCT (n=43), MRI (n=18), or both, as indicated by the respective surgeon. The results were compared with those of surgical exploration and IOUS (n=52), as well as with the pathological examination of the resected liver specimen. In group A, 52 malignant lesions were detected by histopathology. By each of the preoperative examinations (IOUS, HCT), 54 lesions were suspected of being malignant. Thirteen HCCs were missed by HCT (for IOUS: n=4) and 15 lesions were false-positive (for IOUS: n=6). Thirty-nine of 52 lesions were verified to be true-positive by HCT in contrast to 48/52 by IOUS, which resulted in sensitivities of 75% (HCT) and 92% (IOUS, P=0.017), respectively. In group B, the sensitivity of CT was 77%, HCT 90%, MR 93%, and IOUS 99% (P<0.01). In 10%, the strategy of surgical treatment was changed because of IOUS findings. IOUS offered relevant additional information in 6%. Even after sufficient preoperative evaluation, IOUS can provide additional information that frequently has a remarkable impact on surgical decision-making. Identification of HCC is commonly hampered by coexistent cirrhosis. Identification of lesions and orientation of borders to non-tumorous tissue are assessed reliably by IOUS. Thus, IOUS remains a mandatory tool in patients treated by locoregional surgical modalities such as resection, cryotherapy, and intraoperative ethanol instillation for HCC even after refinement of radiological technologies.