The authors of the article analyze more than 30-year experience of surgical treatment of adrenal gland diseases, offering a detailed description of clinical and morphological features of the main nosological forms such as Itsenko-Cushing disease and syndrome, primary hyperaldosteronism, pheochromocytoma, incidentaloma, and malignant adrenal tumors. The paper contains basic diagnostic criteria, indications to operative treatment, and extents of surgery for each of the diseases considered, as well as comparative analysis of peculiarities of conventional ("open"), and endoscopic adrenal gland surgeries. The article demonstrates significance of various immunohistochemical markers in differentiation between malignant and benign adrenal tumors.