Aplastic anemia is an uncommon complication of thymoma and is extremely infrequent after the surgical removal of a thymic tumor. Aplastic anemia is a result of marrow failure and is characterized by peripheral pancytopenia and severely depressed marrow cellularity; it may be an autoimmune manifestation of thymoma. As thymoma-associated hematological dyscrasias, which include pure red cell aplasia, aplastic anemia and myasthenia gravis, are supposed to be of immunologic origin, two cases of very severe aplastic anemia following the resection of lymphocytic thymomas treated with immunosuppression are herein presented.