Supernumerary nostril is a very rare congenital anomaly, which includes additional nostril with or without accessory cartilage. In the present case of the left supernumerary nostril, a small cavity of around 3 mm diameter and accessory lower lateral cartilage were present. The cavity was lined with mucous membrane and filled with mucoid discharge .Nasal endoscopy of accessory nasal cavity revealed that it was small as compared to normal nasal cavity and did not communicate with the ipsilateral nasal cavity. The diameter of the normal anterior nasal opening was less on left side as compared to right side. Unilateral supernumerary nostril may occur because of the Assuring of the lateral nasal process during fetal growth.