To evaluate the visual and anatomical outcomes and safety of bimanual microincision vitreous surgery for severe proliferative diabetic retinopathy. Retrospective review of 315 eyes of 282 patients who underwent 23-gauge or 25-gauge pars plana vitrectomy with bimanual membrane dissection for diabetic tractional detachment from January 2007 to September 2016. Minimum follow-up was 3 months, and the average duration of follow-up was 23 months (range 3-100 months; median 15 months). Outcome measures were best-corrected visual acuity, anatomical success, and postoperative complications. Postoperatively, 84.3% of eyes improved (>2 lines), 10.5% were stable, and 5.4% worsened (>2 lines). Comparing gauges, two-line improvement was seen in 87.4% of 23-gauge eyes compared with 79.7% of 25-gauge eyes (P = 0.029). Mean peak best-corrected visual acuity improved from 20/930 (1.67 ± 0.63) preoperatively to 20/120 (0.78 ± 0.63) postoperatively (P < 0.001). Primary reattachment was achieved in 310 eyes (98.4%) and final reattachment in 312 eyes (99%). Recurrent vitreous hemorrhage was the commonest postoperative complication (18.4%). Lower incidence of recurrent vitreous hemorrhage was seen with 25 gauge (13.5%) compared with 23 gauge (22%, P = 0.038). Epiretinal membrane formation (7.9%), intractable glaucoma (2.5%), and endophthalmitis (0.6%) were some of the other postoperative complications. Sustained visual improvement, anatomical restoration, and low complication rates were obtained in complex situations with bimanual microincision vitreous surgery in a large series. Visual outcomes were poorer in older age group, tractional retinal detachments involving macula, and eyes with extensive membranes and with silicone oil as tamponade. Both 23-gauge and 25-gauge groups were comparable in relation to visual improvement, anatomical success, and intraoperative and postoperative complications.