ABSTRACT—The effect of corticosteroid pretreatment on interferon alfa treatment of chronic non‐A, non‐B or C hepatitis was evaluated in an open, randomized, controlled study. Normalization of the serum alanine aminotransferase level, which suggested complete response, was recorded in 14 (56%) of 25 patients at the end of a 6‐month treatment with 3 million units of interferon alfa three times weekly alone. Prednisolone withdrawal followed by the same interferon alfa treatment resulted in complete response in 14 (61%) of another 23 patients. Both of these rates are significantly higher than the spontaneous ALT normalization rate of 9% observed in 2 of 22 patients during the same period (p<0.01). ALT normalized within 2 months of interferon therapy in most (89%) of the complete responders. Of the patients pretreated with prednisolone, 43% showed a “rebound” following prednisolone withdrawal and 89% of the patients with “rebound” responded to subsequent interferon therapy. The cumulative probability of sustained remission in patients with and without prednisolone pretreatment in a 24‐month period of follow‐up after the end of therapy was 79% and 30%, respectively (p<0.05). Clinical relapse mostly (85%) occurred within 3 months after the end of therapy. No obvious factor could be identified as a predictor of response or relapse. The results of this study suggest that prednisolone withdrawal tends to enhance the durability of the beneficial effects of interferon alfa therapy in patients with chronic non‐A,