Bone marrow and hematopoietic stem cell transplants are life saving procedures for a variety of hematologic malignancies. Unfortunately, long-term survival is significantly impacted by the development of invasive fungal and bacterial infections, in part attributable to innate and adaptive immunologic defects post-transplant. This review focuses specifically on neutrophil function after autologous and allogeneic bone marrow and hematopoietic stem cell transplant.