Material and Methods: Abdominal US and CT scans of 50 pediatric cystic fibrosis (CF) patients were evaluated to search for specific data that can be attributed to the involvement of the hepatobiliary system. The liver findings of the two patients who were HBs antigen carriers ere excluded from the study. Results: 30 out of 48 patients had at least one abnormal finding of liver on CT and/or US. Although increased echogenicity of the liver was detected in 24 of 48 patients (50%), only six of these (12%) were regarded as steatosis according to CT criteria of low attenuation values. CT and US scans both showed unique multilobular fatty pattern, described as 'pseudomasses' in three patients. Increased periportal echogenicity was seen in 18 (37%) patients on US. while CT could not demonstrate any sign of increased periportal thickness. Findings of cirrhosis were present in five patients with either modalities. Lymph nodes of less than 10-15 mm in diameter ere detected at the hepatico-duodenal ligament in 18 (37%) patients. Anomalies of the gallbladder (absence or microgallbladder or stone) were detected in 12 cases (24%). Conclusion: Although US is the most widely used modality in CF patients. CT and US correlation will help to better delineate the abnormalities between steatosis and periportal fibrosis and increase the sensitivity of the imaging methods to achieve the most accurate diagnosis. (C) 2002 Elsevier Science Ireland Ltd. All rights reserved.