Thyroid parenchymal disease is an inflammatory disease that occurs in the thyroid parenchyma due to autoimmunity or infection. The differential diagnosis of thyroid parenchymal disease is based on clinical manifestation, physical examination, and serological findings. However, ultrasonography of thyroid has also a role in the diagnosis of thyroid parenchymal disease. This review describes common findings of ultrasonography in each thyroid parenchymal disease.