Neuroblastoma is the most common extracranial solid tumor in children. Mild hypertension is a frequent symptom, presumably an effect of catecholamines that tumors release. Reported herein is the rare occurrence of severe hypertension and subsequent heart failure attributable to adrenal gland neuroblastoma. A 3-year-old boy presented with anterior chest wall protrusion. Physical examination revealed severe hypertension, and left-sided cardiac failure was evident by echocardiography. Catecholamine metabolite (norepinephrine) levels were increased in serum (>2,000 pg/mL) and in urine (1,350.5 µg/day). Abdominal computed tomography scan showed a 7 cm solid mass arising from right adrenal gland. Oral phenoxybenzamine was given for hemodynamic stabilization, and right adrenalectomy was performed to remove an apparent pheochromocytoma. Ultimately, the pathologic diagnosis was ganglioneuroblastoma. Both hypertension and cardiac failure resolved postoperatively.