To the best of our knowledge this is the reported first case of the successive occurrence in the same patient of chronic active hepatitis and acquired pure red cell aplasia, both probably of autoimmune origin. The diagnosis of autoimmune hepatitis was based on the presence of characteristic lesions at the examination of the liver biopsy specimen, high titer of anti-smooth muscle antibodies in the serum, and remission obtained by steroid therapy. Erythroid aplasia, which appeared during the course of this treatment, was revealed by a regenerative anemia (4.4 g Hb/100 ml) and proved by bone marrow aspiration and biopsy. In vitro bone marrow culture was normal, suggesting the in vivo presence of an inhibitor of erythroblastic differentiation. Red cell aplasia was cured by cyclophosphamide (100 mg/day during 56 days). No recurrence was noted until the death of the patient, which occurred one year later, due to hepatic cholangiocarcinoma. Action of cyclophosphamide on the pure red cell aplasia suggested the immune origin of this disease. The liver and the bone marrow erythroid lineage have probably been the successive targets of immunologic dyscrasia.