Functional autonomy of the thyroid gland (FATG) remains an important problem due to iodine deficiency over the whole territory of Russian Federation and the fact that iodine prophylaxis has not been conducted for a long period of time. Since iodine deficiency affects the thyroid gland (TG) as a whole, the formation of nodules is not limited to a single lobe, but leads to the development of multinodular goiter, the main feature of which is morphological and functional heterogeneity of TG tissue. Active cell proliferation in the iodine deficiency related goiter is associated with an elevated risk of somatic mutations, including activating mutations leading to thyrocyte functional autonomy. Diagnosis is often late due to the absence of any specific complaints in most patients. Hence, the pathology is often an accidental finding and is mostly revealed in patients with cardial diseases. For a long time, TG scintigraphy has been the only method allowing the diagnosis of FATG, while other techniques, such as ultrasonography and the measurement of the hormone levels in blood, only make it possible to assume the presence of this pathology. Nowadays, fine needle biopsy plays an important role since it gives a possibility to obtain direct cell-level findings concerning the morphological structure of TG nodules and, in some cases, the functional condition of cells. Of late, great importance to clinical practice has been attached to new developments in FATG diagnostics, immunomorphological (immunocytochemical and immunohistochemical) techniques in particular. Most probably, new techniques of FATG verification will be based upon the study of TSHR as the specific marker of this pathology, and it will be possible to use immunocytochemical assay as an additional diagnostic method for the verification of autonomic nodular formations as early as right after the puncture.