OBJECTIVE Candidates for diabetic vitrectomy often have concurrent renal dysfunction and have undergone hemodialysis. The influence of hemodialysis on the surgical outcome of vitrectomy was investigated. METHODS Vitrectomy was performed on 76 eyes with proliferative diabetic retinopathy in 66 patients with end-stage renal failure who had undergone hemodialysis. Follow-up was longer than 1 year. RESULTS No uncontrollable hemorrhage occurred either during or immediately after the surgery. Final visual acuity after surgery was the same as preoperative visual acuity in 31.5% of the eyes; improvement was seen in 60.5% of the eyes. A final visual acuity of 0.2 or better was observed in 57.6% of the eyes. Major postoperative complications included recurrent vitreous hemorrhage, rhegmatogenous retinal detachment, fibrin clot formation, neovascular glaucoma, flat anterior chamber, and a transient rise in intraocular pressure. CONCLUSIONS Renal failure and hemodialysis do not appear to have a deteriorative influence on the outcome of vitrectomy for proliferative diabetic retinopathy. A flat anterior chamber seems to be a rare and perhaps unique postoperative complication of gas-filled eyes in patients who have undergone hemodialysis.