Advances in the management of the pulmonary complications of cystic fibrosis may result in an increasing prevalence of patients with chronic liver disease which may, therefore, become more important in the long-term management of cystic fibrosis patients. However, no simple and reliable test is available for the diagnosis of liver disease in cystic fibrosis. In particular percutaneous liver biopsy is highly inaccurate and potentially dangerous. Imaging techniques, including real-time ultrasound scanning, have been used to evaluate the hepato-biliary system in cystic fibrosis and may represent the best available techniques for documenting hepatic involvement. The purposes of this study were to construct an ultrasound scoring system using three cardinal features of hepatic ultrasound in cystic fibrosis: coarseness of the parenchyma, nodularity of the liver edge and increased periportal echogenicity, to enable the accurate, early diagnosis of liver involvement in cystic fibrosis. The scoring system was validated by correlating the results against ultrasound markers of portal hypertension, clinical and haematological data. The scoring system proved to be reproducible and to correlate well with the markers of hepatic disease detailed above. The results also suggest that the scoring system may allow the identification of patients with pre-cirrhotic chronic liver disease and so may prove of value in selecting a sub-group of patients more likely to respond to therapy.