The role of Parvovirus B19 in acute leukemia is under debate. This study aimed to detect parvovirus B19 DNA together with its antibodies in the sera of children with recent acute leukemia and those with acute leukemia receiving chemotherapy to clarify the contribution of this infection to changes observed in hematological and clinical presentations in these populations. Two groups were included: Group I comprised 45 children with acute leukemia receiving chemotherapy and Group II comprised 40 children with recently diagnosed acute leukemia. Serum parvovirus B19 IgG and IgM were investigated by enzyme-linked immunosorbant assay and the virus DNA was sought by polymerase chain reaction assay. Viral DNA was found in 22.2% of Group I patients and in 45% of Group II patients. Hemoglobin levels were significantly reduced in patients with recent infection, accompanied by statistically significant lymphocytosis in Group I patients. Group II patients with recent infection had marked neutropenia with lymphocytosis and thrombocytopenia. There was statistically significant lymphadenopathy and hepatosplenomegaly in patients with recent infection in both groups. Parvovirus B19 infection is an important cause of cytopenia in children with acute leukemia both when recently diagnosed and receiving chemotherapy. This can affect the schedule of chemotherapy. Moreover, the presence of Parvovirus B19 is associated with marked lymphadenopathy and hepatosplenomegaly.