Composite pheochromocytoma-ganglioneuroma is one of the mixed neuroendocrine-neural tumors composed of pheochromocytoma and other neural crest derivatives. To date, less than 50 cases of composite pheochromocytoma have been reported, and about 70% of the accompanying tumors were ganglioneuromas. Here, we describe six cases of composite pheochromocytoma-ganglioneuromas in five men and one woman, aged 33 to 64. The size of the tumors ranged from 3.0 to 11.0 cm, and four out of the six presented with intermittent onset of hypertension, palpitation, or dizziness. Microscopically, each tumor was composed of large pleomorphic shaped chromaffin cells arranged in the Zellballen patterns characteristic of pheochromocytoma, and they were mixed with clusters of mature ganglion cells and bundles of spindle-shaped Schwann cells characteristic of ganglioneuroma of variable proportions. All were successfully treated laparoscopically, and none were associated with multiple endocrine neoplasm syndrome or neurofibromatosis. Preoperative diagnosis of a composite pheochromocytoma-ganglioneuroma is impossible because of the low incidence rate, and the radiological findings and symptoms are similar to those of typical pheochromocytomas. Although the significance of microscopic detection of the nonpheochromocytoma component from pheochromocytoma has not yet been clarified, microscopic identification of the composite pheochromocytoma-ganglioneuroma is important because cumulative cases are used in an effort to predict the behavior of this composite tumor. (Endocrinol Metab 26:340-344, 2011)