Background: The internal branch of superior laryngeal nerve (IbSLN) is known as, principal sensory nerve of the larynx because the IbSLN provides most sensation to the laryngeal mucosa and the hypopharynx, it plays a vital role in the protection of the airway by initiating reflex glottic closure during swallowing, coughing, and vomiting . The internal branch of superior laryngeal nerve (IbSLN) gives motor fibers to the interarytenoid muscle. So the nerve supply of interarytenoid is yet controversial. Objective: To study the gross anatomy of internal branch of superior laryngeal nerves (IbSLNs) in 25 human larynges. Methods: Whole larynges were processed to clear all soft tissue in Department of Anatomy at Thanjavur Medical College,Thanjavur. Then the main laryngeal nerves and the muscles they innervate were dissected and analyzed. Results: The present study shows that the IbSLN originates at the level of C2 vertebra and lies parallel and medial to the superior laryngeal artery in 82%, pierces medial to the midline of thyrohyoid membrane in 50% and branched distal to thyrohyoid membrane in 76% of the dissected specimens. Galen anastomosis is found in 52% of specimens in the present study. Conclusion: The internal branch of superior laryngeal nerve( IbSLN ) injury during Spine surgery, thyroid surgery and during carotid endarterectomy, causes loss of cough reflex and therefore it needs knowledge regarding the detailed anatomy of this nerve. However, the dual innervations of the larynx by superior laryngeal nerve [SLN] decreases the risk of cough reflex loss.