Background: Lateral pathologies of the frontal sinus are difficult to visualize and treat with classical endoscopic sinus surgery (ESS) using rigid endoscopes and instruments. Hence, they often require extended endoscopic or external approaches. Methods and Results: We describe the advantages of using interventional flexible bronchoscopy in frontal ESS without extended approaches in 2 illustrated cases: (1) A fungus ball in the frontal sinus with a frontoethmoidal cell. The flexible bronchoscope allowed treatment of all recesses of the frontal sinuses and the opening of a frontoethmoidal cell through a Draf IIa. (2) A revision surgery with a frontoethmoidal cell obstructing drainage pathway was successfully treated with this same technique. Patients did not experience complications or recurrent symptomatology after, respectively, 4 and 15 months of follow-up. Conclusion: Flexible bronchoscopy allows a good visualization and treatment of lateral frontal sinus pathologies through limited endoscopic approaches. Through-the-scope instruments permit the resection of frontoethmoidal cells.