Erythropoietic and granulopoietic expansion after bone marrow transplantation (BMT) are reviewed in 60 allogeneic and autologous BMT. Morphological dyserythropoiesis was more prominent than dysgranulopoiesis. Dyserythropoiesis was present with increased HbF synthesis and i antigen expression. We did not find nocturnal paroxysmal hemoglobinuria and leukocytic alkaline phosphatase level was high. CFU-GM progenitors were still reduced in number 1 year after BMT. The clusters/colonies ratio, increased at day 12 after BMT was normal by day 100. No difference between autologous and allogeneic BMT was observed.