A 14-year follow-up of 153 haemophilic patients treated with clotted factor concentrates was made to assess liver function. Investigations included measurement of alanine amino transferase (ALT), immunoglobulins, HIV antibody, HBsAg, antibody to HBs and HBc antigens, antibodies to HCV (assayed by ELISA-2 and by RIBA-2) and HCV viraemia assessed by PCR. Assessment of liver function also included liver ultrasound scan and oesophageal X-ray. A positive correlation was found between abnormal liver functionand age, HIV infection, HBV infection, HCV infection and hepatomegaly. However, there was no correlation between abnormal liver function and annual clotting factor concentrate use. The increasing incidence of liver insufficiency with increasing age is likely to result in substantial morbidity and mortality amongst haemophilic patients.