Background A frontal sinus leak is uncommon and is seen in ∼15% of cases of patients with cerebrospinal fluid (CSF) rhinorrhea. Now, endonasal endoscopic techniques have been reported to reconstruct skull base defects in the frontal sinus with a favorable outcome. Objective To review our experience in the repair of frontal sinus CSF leaks through an endonasal endoscopic approach. Methods Twenty-four patients with a frontal sinus leak who underwent endonasal endoscopic repair entered the study. Clinical presentation, location, frontal sinusotomy, graft material, follow-up, and frontal sinus status were evaluated. Results Among >100 cases of surgically repaired CST rhinorrhea, the frontal sinus was the site of the leak in 24 patients (mean age, 28.9 years; mean follow-up, 22 months). The etiology consisted of spontaneous leak and traumatic leak; whereas patients with skull base reconstruction after removal of tumor were excluded. Surgical approaches included Draf IIb, Draf III, Draf IIa in 20, 3, and 1 patients, respectively. Tree autografts as two-layer inlay fat–muscle and onlay fascia lata were used in the majority of patients. A success rate was achieved in 95.83% of the patients. Conclusion Endonasal endoscopic repair of a frontal sinus leak was a successful procedure, with a low failure rate and minimal morbidity.