The e antigen HBeAg and its antibody anti-HB have been said to be predictive of chronicity and resolution, respectively, in viral hepatitis. We found, as have others, a specific association with hepatitis B virus-induced disease. In addition, detectability of HBeAg in the acute phase of type B hepatitis was followed by a sixfold higher incidence of chronic hepatitis. Unfortunately, the prediction was erroneous in 65% of positive cases and 6% of negative cases. In chronic hepatitis, HBeAg did not necessarily disappear in advance of resolution, and its disappearance did not necessarily indicate resolution. Two patients with acute hepatitis progressing to chronicity were anti-HBe-positive in both phases, as were seven (5%) with chronic hepatitis. For individual patients, therefore, HBeAg and anti-HBe are not prognostically useful indexes.