Leukoerythroblastosis is a rarely observed disease characterized by the presence of leukocytosis, erythroid and myeloid blast cells in peripheral blood. To our knowledge, it had not been diagnosed in a premature newborn before the case we report have.A female baby weighing 1164 grams, who was born prematurely at the 29th week of gestation by Cesarean section was referred to our newborn intensive care unit due to prematurity and respiratory distress with no prenatal pathological findings. Physical examination revealed tachypnea and hepatosplenomegaly. Routine laboratory measurements showed significant leukocytosis (85,000/mm3) and anemia (Hb: 9.6 g/dL and Hct: 27.6%). The platelet count was normal. The peripheral blood smear suggested leukoerythroblastosis with the presence of nucleated erythrocytes, monocytosis, and 4% blasts. Bone marrow cytogenetic examination was normal. Parvovirus B19 Ig G and M serology were detected to be positive.The etiological factors observed in leukoerythroblastosis occurring during neonatal and early childhood period are congenital-postnatal viral infections, juvenile myelomonocytic leukemia and osteopetrosis. To our knowledge, no case of leukoerythroblastosis in such an early phase has been reported in the in literature. As a result, premature delivery and leukoerythroblastosis were thought to have developed secondary to intrauterine parvovirus B19 infection.Leukoerythroblastosis is a rarely observed disease characterized by the presence of leukocytosis, erythroid and myeloid blast cells in peripheral blood. It is reported that it can be observed following hematologic malignancies especially juvenile myelomonocytic leukemia, acute infections, hemolytic anemia, osteopetrosis, myelofibrosis, neuroblastoma and taking certain medicines. To our knowledge, it has not been diagnosed in a premature newborn before. Here we the case of a newborn who was referred to our intensive care unit due to being born prematurely at the 29th week of gestation and diagnosed with leukoerythroblastosis.