For the first time the surgical technique of right and left adrenalectomy by a posterior percutaneous retroperitoneoscopic access is described. The adrenal gland is mobilized after creation of a pneumoretroperitoneum and insertion of 3-4 trocars beneath the 12th rip. Indications for this new method are small, benign adrenal tumours or adrenocortical hyperplasias. By this method, the potential advantages of a posterior approach and minimally-invasive surgery are combined. This surgical technique might become a major advancement in adrenal surgery.