We describe a technique of mini-thoracotomy to plicate the paralyzed hemidiaphragm with thoracoscopic assistance. Most of the hemidiaphragm can be plicated expeditiously under direct vision with light derived from a posterior thoracoscope placed in the auscultatory triangle. Videoscopic vision is employed only occasionally when the view of the posteromedial hemidiaphragm is obscured. Continuous suture traction can be easily applied through the mini-thoracotomy, thus maintaining suture tension and enabling maximal inversion of the elevated hemidiaphragm. (C) 1999 by The Society of Thoracic Surgeons.