The authors describe two women with a history of partial red-cell aplasia of the bone marrow without any remissions for 2 and 3 years, followed by the development of erythromyelosis. The latter lasted from 1 to 2 years, the total illness duration being 4 to 5 years. All the attempts to achieve remissions with the use of splenectomy, mono- and polychemotherapy with a purpose of immunosuppression ended in failure. Partial red-cell aplasia is viewed as preleukemia.