The main aim of this study was to investigate the role of N-(2,4,6 trimethyl-3-bromophenylcarbamoylmethyl) iminodiacetic acid (IDA; Mebrofenin) scintigraphy in follow-up assessments of the biliary system in patients with cystic fibrosis associated liver disease. Fourteen patients from a study published in 1996 were re-examined after a mean interval of 4.7 years from their initial study, in which diisopropylphenyl carboxymethyl iminodiacetic acid (DISIDA) was used. The results of ultrasound, liver function tests and clinical examination were also compared. Twelve of the patients had been treated with ursodeoxycholic acid and taurine in the interim. Five subjects' IDA examinations showed a slight improvement on follow-up, six deteriorated, two were unchanged, whilst one demonstrated a 'mixed picture'. Overall, nine patients deteriorated in one or more of the tests. No patient showed a decline in all four investigations and only two in three. There was poor correlation between the various follow-up examinations, with different patients showing a decline in some tests but not others. This may be due to the mixture of functional and anatomical studies utilized, their differing sensitivies, and the fact that deterioration in one did not necessarily affect another. In conclusion, follow-up of hepatobiliary disease in patients with cystic fibrosis cannot be encompassed by one method alone. If early detection of disease progression would affect management, patients will continue to require a number of investigations rather than a single test.