Background Additional mechanical pleurodesis for the treatment of primary spontaneous pneumothorax (PSP) is believed to reduce the recurrence of PSP, and a covering procedure with absorbable mesh also shows comparable results. This study was conducted to determine whether additional mechanical pleurodesis would be effective in reducing recurrence after thoracoscopic wedge resection and covering procedure. Materials and methods Between May 2003 and August 2005, 99 patients underwent thoracoscopic bullectomy with staple line covering with absorbable cellulose mesh and fibrin glue followed by an additional mechanical pleurodesis. These patients were compared with 98 patients who underwent thoracoscopic bullectomy with staple line coverage alone. Results The additional mechanical pleurodesis group had findings comparable to those of the coverage group for duration of postoperative chest drainage, length of hospital stay, and complication rate. After median follow-up of 29.2 months, postoperative recurrence occurred in four patients (4.0%). Conclusions Additional mechanical pleurodesis after covering procedure is also effective in decreasing postoperative recurrence of PSP.Keywords Primary spontaneous pneumothorax (PSP) Á Mechanical pleurodesis Á Video-assisted thoracic surgery (VATS) Primary spontaneous pneumothorax (PSP) is well known to have high recurrence rates if not treated appropriately. There are ongoing debates on how to most effectively lower its recurrence after the first clinical treatment. Conservative treatments, such as needle aspiration or pleural drainage with a chest tube, show rather high recurrence rates, varying from 11% up to 36% [1]. Active surgical operations using thoracoscopy have resulted in a significant reduction in overall morbidity. However, wedge resection alone by video-assisted thoracoscopic surgery (VATS) has caused some doubts due to the high recurrence rates, hence various pleural symphyses have been performed in order to reduce its recurrence rate. In a previous retrospective study, Sakamoto et al. found that a staple line coverage procedure, which helps reduce the recurrence rate by minimizing the formation of new blebs near the staple line, showed a recurrence rate comparable to that of pleural symphysis, and as a result it has been confirmed that this procedure is effective in decreasing the recurrence rate of PSP [2,3].In this context, some questions have been raised as to whether additional mechanical pleurodesis can further reduce the recurrence rate if performed simultaneously