Three thousand six hundred and ten patients with acute hepatitis in two large hospitals in Dhaka city were tested for HBsAg. Besides, 780 commercial blood donors, 126 doctors and 576 apparently healthy persons were also tested. Passive haemagglutination technique was applied for this test. Patients with post-transfusion hepatitis and doctors with acute hepatitis showed the highest incidence, being 60% and 65.5% respectively. HBsAg was detected only in 15.4% of children and 27.2% of adult patients with acute hepatitis.