Two patients with hypogammaglobulinemia and chronic active non-A, non-B hepatitis caused by intravenous gammaglobulin substitution were treated long-term with alpha-2b interferon (Introna). Both achieved normal aminotransferase levels within 2-12 weeks after initiation of interferon therapy. One patient was rebiopsied after 6 months of therapy and showed some degree of improvement in the liver inflammatory activity. The beneficial effects warrant a randomized controlled study.