In this study, the authors describe the first report of 2 patients of fat prolapse into the nasal cavity by orbital blowout fracture. The patients were a 58-year-old male and an 86-year-old female. The patients could not attain binocular single vision in any eye position because of severe impairment of the extraocular muscle motility. Computed tomographic images of both patients revealed orbital blowout fractures with orbital fat prolapse into the nasal cavity. The fractures were reduced under transconjunctival/transcaruncular and endonasal endoscopic approaches. Six months postoperatively, the patients attained a binocular single vision field, including in the primary eye position.