A highly specific radioimmunoassay was used to measure the total plasma concentrations of the three principal unconjugated oestrogens: oestrone E1, oestradiol E2, and oestriol E3 in normal males and in 21 males with various forms of chronic liver disease. In addition, the unbound concentration of plasma E2 was established in the same group. About half of the patients with liver disease had overt feminising changes. Total and unbound plasma E2 concentrations were within the normal range in all patients. Total plasma E1 was significantly elevated only in those patients with liver disease and gynaecomastia, and a similar trend was seen for total plasma E3.