The comparative evaluation of thyroid pathology in different regions should include biopsy and autopsy examination. Morphological research (cytological and histological methods) implies 3 steps: preoperative, intraoperative and postoperative. The results of cytological and histological examination should be properly used by clinicians. For successful comparative ecological research it is necessary to use reliable methods of investigation of thyroid goiter and thyroid tumours. These methods provide evaluation of real morphofunctional state of thyroid pathology in different regions.