BACKGROUND: High-resolution endoscopes and the advent of endoscopic instruments for sinus surgery provide surgeons with excellent endonasal visualization and access to the orbital walls. OBJECTIVE: To demonstrate repair of orbital floor blowout fractures through an intranasal endoscopic approach that allows repair of the orbital floor fracture and elevation of the orbital content using a balloon catheter without an external incision. DESIGN: This study was a retrospective analysis of 11 patients who underwent surgical repair of orbital floor fractures from September 1994 to June 1997. There were 10 male patients and 1 female patient, aged 12 to 32 years (mean age, 24 years). These patients had undergone primary repair of pure orbital blowout fractures and were followed up at least 6 months after surgery. RESULTS: There were no intraoperative or postoperative complications. Nine patients showed a complete improvement of their diplopia. Two patients with posterior fractures showed persistent diplopia, which was well managed by prisms. CONCLUSION: Endoscopic repair of the orbital floor blowout fracture using an endonasal approach appears to be a safe and effective technique for the treatment of diplopia.