The surgical results for 248 eyes that underwent vitrectomy for diabetic vitreous hemorrhage showed that at the final examinations, 194 (78%) had improved visual acuities, 43 (17%) had worse visual acuities, and 11 (4%) were unchanged. Of the 248 eyes, 60 (24%) had final visual acuities of 20/40 or better, 128 eyes (52%) had final visual acuities of 20/50 to 20/800, and 60 (24%) had final visual acuities worse than 20/800. Eyes with preoperative iris neovascularization had a substantially worse visual result than eyes without this complication. Eyes in which the lenses were removed during vitrectomy also had worse visual results, primarily because they had a higher cumulative incidence of postoperative iris neovascularization and neovascular glaucoma.