Abstract: Thyroid is a highly vascular endocrine gland which is placed anteriorly in the neck. Thyroid hemiagenesis is a rare congenital anomaly in which one thyroid lobe with or without an isthmus fails to develop. We are presenting such a case detected accidentally during routine cadaveric dissection. This condition usually is undiagnosed as it leads to symptoms only when it is associated with other conditions. It is one of the contributing factors for hypothyroidism. It may develop as a sporadic case or familial or due to some genetic abnormalities. Four different genes were identified for development of thyroid but every case of hemiagenesis was not associated with mutations of these genes. Molecular mechanism of development of hemiagenesis needs to be explored.