During September and October of 1977, a total of 342,407 apparently healthy blood donors were screened for HB(s)Ag by reversed PHA, and 6,342 (1.9%) asymptomatic carriers of HBV were identified. Prevalence of HB(e)Ag and anti-HB(e) among HBV carriers was tested by our immunodiffusion method after serum samples had been concentrated threefold. The results were evaluated with reference to sex and age of donors, as well as HB(s)Ag titre and s-GPT level in the serum. HB(e)Ag was found slightly but significantly more often in male donors than in female donors (19.1 vs. 16.7%). In contrast, anti-HB(e) was found less frequently in males than in females (49.6 vs. 53.1%). Frequency of HB(e)Ag decreased, while frequency of anti-HB(e) increased with age both in male and female carriers. The prevalence of HB(e)Ag increased in parallel with the titre of HB(s)Ag, whereas the prevalence of anti-HB(e) was approximately reciprocal to it. An abnormally high value of s-GPT (41 Karmen U/ml or more) was found in 10.0% of the carriers with HB(e)Ag, contrasting with 3.4% of those with anti-HB(e).