The results of surgical treatment of 126 patients with "hormonally inactive" and catecholamine secreting tumors of the adrenals were studied. Among them 2 cases (1.6%) of "dumb" pheochromocytoma were diagnosed. The clinical observations have shown the difficulties in the diagnosis of "dumb" pheochromocytoma before operation, risk of performing adrenalectomy and necessity to correct hemodynamic disorders during anesthesia in connection with latent catecholamine activity. The laboratory and instrumental means of examination of patients with suspected "hormonally inactive" tumor of the medullary substance of the adrenal are proposed. The variants of prevention and arrest of hemodynamic disorders during ablation of the "dumb" pheochromocytoma were considered. When the "dumb" pheochromocytoma had the diameter less than 5 cm and the adequate preparation was conducted the authors propose a laparoscopic access for adrenalectomy on the right, and retroperitoneoscopic access on the left. The detection of the catecholamine secreting tumor of more than 5 cm diameter, when problems with the clipping of the central vein of the adrenal take place, open accesses should be preferred--mainly thoracophrenotomy in the X intercostal space. If it was not possible to prove "dumb" pheochromocytoma before operation and it was started with endovideosurgical intervention during which it was not possible to first clip the central vein of the adrenal and the risk of hemodynamic disorders was high, the early transition to open operative intervention is thought to be expedient.