© 2014, Haseki Training and Research Hospital. All rights reserved.The most common causes of abdominal mass are neuroblastoma, germ cell tumors, hepatoblastoma and congenital mesoblastic nephroma. Congenital mesoblastic nephroma (CMN) accounts for more than 90% of all renal tumors seen in the first three months of life. Total nephrectomy is curative. Neuron-specific enolase is a glycolytic enzyme that is localized primarily to the neuronal cytoplasm. Its sensitivity is especially high for neuroblastoma and small cell lung cancer. In this paper, we report a newborn with abdominal mass that was firstly considered as neuroblastoma due to calcifications observed on ultrasonography and high levels of serum neuron-specific enolase. After histopathological evaluation of the lesion, the patient was diagnosed as having atypical (cellular) congenital mesoblastic nephroma.