Diagnosis and treatment of neonatal aortic thrombosis is very important because of the high mortality. Eighty percent of the underlying cause is the umbilical catheterizaion. The most common clinical findings are absent femoral pulses, pallor and cold of the lower extremities, difference between the upper and lower extremity limb tensions. Although there is no consensus on treatment, therapeutic options include fibrinolytic therapy, anticoagulation, surgical thrombectomy or a combi nation of these therapies according ta location of thrombosis and clinical findings. This report des cribes a newborn who developed aortic thrombosis, which was attributed to dehydration and MTHFR mutation and which was treated with streptokinase, heparin and low moleculer weight heparin. Copyright © 2012 by Türkiye Klinikleri.