Antibodies to Epstein‐Barr virus and cytomegalovirus, determined by an indirect immunofluorescence technique, were found to be significantly elevated in sera of untreated patients with Hodgkin's disease, as opposed to sera of age‐ and sex‐matched healthy controls. Significantly higher titers were also found in subgroups with clinically advanced disease. This pattern did not hold for histologic subclasses, as significant antibody elevations occurred only in the prognostically favorable types. Australia antibody was demonstrated by counter‐electrophoresis in four patients but in none of the controls. The prevalence of the various antibodies might be explained by a humoral hyper‐reactivity secondary to a cellular immunologic deficiency. The results presented cast some doubt on a specific role of Epstein‐Barr virus in Hodgkin's disease.