Conclusion: Chemical pleurodesis is a safe and convenient procedure that may improve the outcome and reduce the rate of recurrence after thoracoscopic treatment for primary spontaneous pneumothorax. Results: There was no significant difference between the two groups in terms of demographic data, operative findings, and operation time. There was significant decrease in the rate of prolonged air leaks, duration of postoperative chest drainage, hospital stay and the incidence of recurrence in group B patients. Methods: 120 patients undergone video assisted thoracoscopy (VATS) for 1ry spontaneous pneumothorax were retrospectively studied. The patients were divided into 2 equal groups (group A): without chemical pleurodesis after VATS and (group B): with chemical pleurodesis after VATS. VATS procedures included resection of the blebs and mechanical pleurodesis by scrubbing the parietal pleura. Background: Methods to achieve adhesion of the two pleural layers and thus, “obliteration of the pleural apace” have included mechanical abrasion and instillation of chemical irritants. Combination of two methods after thoracoscopic bullectomy has rarely been mentioned in the literatures. The aim of this study is to evaluate the safety and efficacy of additional chemical pleurodesis after thoracoscopic treatment of primary spontaneous pneumothorax.