Although silicone oil is being used with increasing frequency for proliferative vitreoretinopathy (PVR), few studies have reported on its use for severe forms of proliferative diabetic retinopathy (PDR). Vitreous microsurgery with silicone oil tamponade was performed on 34 patients (37 eyes) with refractory severe neovascular glaucoma and/or recurrent retinal detachment (RD) from PDR that failed to respond to conventional techniques including vitrectomy, membrane peeling, gas tamponade and photocoagulation. With all patients followed a minimum of 6 months (mean, 13 months), anatomic attachment was maintained in 26 (70%) of the eyes. At the last follow-up examination, a final visual acuity of at least 5/200 was found in 9 (24%) of 37 eyes and 9 (35%) of 26 anatomically successful cases. Regression of iris neovascularization occurred in 8 (36%) of 22 eyes with rubeosis and the silicone oil was removed in 3 (8%) eyes. Significant complications included band keratopathy in nine (24%) eyes, corneal decompensation in three (8%) eyes, and recurrent retinal detachment in seven (19%) eyes.