A 5-year-old boy presented with headache and hypertension. Screening abdominal ultrasonography showed a 6-cm-sized mass in the left adrenal gland. Laboratory data included urine vanillylmandelic acid/creatinine (208.3 μ g/mg),urine homovanillic acid/creatinine (114.3 μ g/mg),serum epinephrine (237 pg/mL),and serum norepinephrine (1842 pg/mL)-. Metaiodobenzyl guanidine I 123 scintigram,abdominal computed tomography,and abdominal magnetic resonance imaging revealed only left adrenal tumor with no metastasis. Left adrenalectomy was performed transperitoneally,and histopathological diagnosis was an adrenal composite pheochromocytoma associated with neuroblastoma. Immunoreactivity for vimentin was positive in pheochromocytoma,which was negative in neuroblastoma. After operation,the symptom of hypertension disappeared. We should examine the identification of composite pheochromocytoma by immunohistochemistry method in patients with neuroblastomatous elements complicated by severe hypertension,and it is important to carefully monitor urine vanillylmandelic acid and urine homovanillic acid in the examination tests and hypertension in the clinical symptoms,and follow up this patient because of some risk of recurrence and metastasis. A 5-year-old boy presented with headache and hypertension. Screening abdominal ultrasonography showed a 6-cm-sized mass in the left adrenal gland. Laboratory data included urine vanillylmandelic acid / creatinine (208.3 μg / mg), urine homovanillic acid / creatinine (114.3 μg / mg), serum epinephrine (237 μg / ml), and serum norepinephrine (1842 pg / ml) -. Metaiodobenzyl guanidine I 123 scintigram, abdominal computed tomography, and abdominal magnetic resonance imaging revealed only left adrenal tumor with no metastasis. Left adrenalectomy was performed transperitoneally, and histopathological diagnosis was an adrenal composite pheochromocytoma associated with neuroblastoma. Immunoreactivity for vimentin was positive in pheochromocytoma, which was negative in neuroblastoma. After operation, the symptom of blood disappeared. We should examine the identification of composite pheochromocytoma by immunohistochemistry method in patients with neuroblastomatous elements complicated by severe hypertens ion, and it is important to carefully monitor urine vanillylmandelic acid and urine homovanillic acid in the examination tests and hypertension in the clinical symptoms, and follow up this this cause because of some risk of recurrence and metastasis.