In order to assess the frequency of significant liver disease in hepatitis B surface antigen carriers with normal liver tests, 54 such individuals were identified and prospectively followed for 4 to 48 months with monthly liver tests. Upon testing, 4 were found to carry e antigen and 14 carried e antibody (anti-e). During follow-up, only 4 patients, none of whom were e antigen-positive, developed persisting abnormalities in liver tests. Of the 23 patients who underwent percutaneous liver biopsies, normal histologies were found in 2, nonspecific changes (ground glass hepatocytes, focal necrosis, fatty changes, etc.) in 18, and chronic persistent hepatitis (with or without other nonspecific changes) in 3. Chronic active hepatitis and/or cirrhosis, lesions which may carry more serious prognostic implications, were not seen in any biopsies. Two of the 4 e antigen-positive patients consented to biopsy, both of whom had chronic persistent hepatitis. All 6 patients with anti-e who underwent biopsy had ground glass hepatocytes, which were found in only about 50% of the remaining patients. It is concluded that hepatitis B surface antigen carriers should be followed with serial liver tests, and those whom tests remain normal should not be considered for liver biopsy.