Identification, evaluation and treatment of liver disease are increasingly important challenges in children with cystic fibrosis (CF). Liver disease usually presents at puberty and is receiving more attention with improved life expectancy. The abnormal CF transmembrane regulator protein in the apical surface of the biliary epithelium causes the disease. Hyperviscous bile accumulates in the biliary tree causing cholangiocyte and hepatocyte injury, stimulating focal fibrosis. Fibrosis is thought to lead on to cirrhosis over a period of years, a process which is usually asymptomatic. Steatosis and biliary tree anomalies including cholecystitis also occur. Clinical signs of liver disease appear late, by which time cirrhosis may be established. Early diagnosis would allow interventions to be evaluated but there is no gold standard for screening. Currently, regular clinical assessment, measurement of liver enzymes, ultrasound and liver biopsy are all used to evaluate liver disease in CF. Bile acid therapy reverses many markers of the disease but there is no good evidence that progression to cirrhosis can be prevented. A few children with cirrhosis decompensate (demonstrated by falling plasma albumin or coagulopathy) but they do well with liver transplantation. Children with portal hypertension as the sole manifestation of CF liver disease can be effectively managed with a programme of variceal obliteration or porto-systemic shunts.