We describe here the case of a renal transplant recipient treated by sirolimus based immunosuppresive therapy, who developed severe and unusual pancytopenia 2 months after renal transplantation. Parvovirus B19 primo-infection was diagnosed. The first course of intravenous immunoglobulin failed. Bone marrow aspiration confirmed megaloblastic anaemia associated with parvovirus B19. Finally, this infection was succesfully treated by the reduction of immunosuppression combined with a second course of intravenous immunoglobulin.