Neuroblastoma is the most frequent solid malignant tumor in the neonatal period; however, its diagnosis is very difficult in the prenatal one. This kind of tumor has a high morbidity and mortality rate due to the metastatic risk. Its prognosis depends on the affected area, on the extension of the tumor, and on the associated abnormalities. The antenatal ultrasound diagnosis is possible by finding a mixed mass in the adrenal gland. We report a case of a bilateral adrenal neuroblastoma diagnosed by antenatal ultrasonography at the 29th week of gestation. We describe the principal findings and show the contribution of the tridimensional ultrasound on the relationship of the tumor with the nearby structures.