This study was undertaken to assess the frequency of development and the stages of evolution of chronic liver disease in patients with renal failure who are chronic carriers of hepatitis B surface antigen. Cirrhosis or chronic active hepatitis developed in five of 21 patients and could not be predicted by the initial histological appearance or by HLA-A and B typing but was associated with the e antigen in four of the five patients. However, the antigen was not a consistent indicator of a poor prognosis, as the four other e antigen positive patients did not develop chronic liver disease during the period of the study. Transmission of hepatitis B to spouses occurred in four cases, was fatal in one instance, and was associated with e antigen in three of the four. Determination of e antigen status in renal unit patients who are carriers of hepatitis B surface antigen may be of value to the patient and his home environment.