The purpose of the present investigation was to enhance the efficiency of diagnosis of thyroid diseases in irradiated persons. Three hundred persons exposed to radiation in doses of 5 to 250 SeV and the postexposure period was 9 to 48 years. A control group comprised 100 military men unexposed to ionizing radiation. Thyroid ultrasound study and morphological diagnosis revealed diffuse nodular goiter transformation in 66% of the irradiated persons and malignant thyroid neoplasms in 3.7% whereas 38% of the control patients were found to have only benign diffuse nodular thyroid alterations and autoimmune thyroiditis (AIT). The investigation identified the echosemiotic features of nodular masses and AIT in the study group patients and established their association with the pathomorphological changes of the thyroid. The authors note the high efficiency of complex clinicoradiation and morphological studies in detecting thyroid pathology and the priority in establishing an accurate diagnosis at the preoperative stage and in determining management tactics.