In this contribution the authors present the results of treatment by pars plana vitrectomy in a consecutive series of 200 patients with proliferative retinopathy. Anatomical success was achieved in 82% of the cases of simple vitreous hemorrhages, in 63% and 67% respectively of the cases of traction detachment with or without vitreous hemorrhage, and in 55% of the cases of combined rhegmatogenous and traction detachment. Postoperative visual success was generally dependent on preoperative macular findings. Visual success was achieved in 71% of cases where the macula was attached preoperatively, as opposed to only 38% of the patients in whom it was preoperatively detached. Intraoperative retinal complications were less than 1% in cases of simple vitreous hemorrhage, rose to 13%-15% in cases of traction detachment and were quite common (32%) in cases of combined rhegmatogenous and traction detachment. A major goal of this paper was to show that anatomical and visual success as well as intraoperative complications were highly dependent on the degree of surgical difficulty and the stage of the disease. The results support the concept that vitreous surgery should be considered early in the late stages of proliferative diabetic retinopathy.