This paper reports a rare case of a left sided thyroid hemiagenesis associated with papillary carcinoma. Thyroid hemiagenesis is a rare congenital anomaly resulted from failure of development on one of the thyroid lobes. Among several thyroid developmental anomalies, hemiagenesis is considered to be the rarest anomaly. In world literature to date, only about 310 cases have been reported. We present a case of thyroid hemiagenesis of the left lobe and isthmus in a 51-year-old female, along with radiological and operative findings. Our report can give the idea that the thyroid hemiagenesis may not influence the development of parathyroid glands.