Abstract: Objective :To evaluate the efficacy and safety of endobronchial brachytherapy for ma-lignant airway obstruction with ¹²⁵I seeds. Methods :Patients with malignant atelectasis underwent en-dobronchial brachytherapy with ¹²⁵I seeds implanted via cricothyroid membrane puncture that werethen suspended in the airway, guided by fibreoptic bronchoscopy.The treatment time was threemonths. Results :Of the 9 cases, 4 patients got complete relief, making the effective rate 44%. Cough,hemoptysis and chest pain occurred in 5 patients. Complications such as inflammatory granuloma inthe neck and laryngeal malaise occurred in 2 patients and 1 patient, respectively. Conclusion :Endo-bronchial brachytherapy with ¹²⁵I seeds for cancerous atelectasis is simple, safe and effective.