Congenital leukemias are a rare group of hematologic neoplasms with a wide range of clinical signs and symptoms. Here we reported a neonate presenting with jaundice, pleural effusion and ascites. The total protein and serum albumin were markedly low at 48 and 12 g/L. Computerized tomography showed the density of liver was asymmetry with several hypoechoic regions. Initial blood routine examination revealed only thrombocytopenia while blood white cells increased to 30.0×10(9)/L with 17% blast cells several days later. Bone marrow biopsy showed the proportion of blasts and promonocytes increased and she was diagnosed as acute monoblastic leukemia.