Ten eyes developed fibrovascular ingrowth from the sclerotomy following closed vitreous surgery. The complication was detected by examining all patients postoperatively by indirect ophthalmoscopy and biomicroscopy with a three-mirror lens. The average follow-up was 13.2 months. Nine patients had proliferative retinal disease prior to surgery and related systemic disease. In six eyes, useful vision was lost due to the ingrowth. In three eyes, a stabilization occurred. In one eye, that of a 12-year-old girl with an undefined syndrome of cochlear and retinal neovascularization, the ingrowth involuted. Rubeosis iridis was observed in 6 eyes that developed vascular ingrowth as opposed to 11 eyes in a control group of 78 eyes. Eyes with rubeosis iridis should not have vitreous surgery, and careful dissection of the Tenon capsule should be done over the sclerotomy.