In patients with proliferative diabetic retinopathy rebleeding after pars plana vitrectomy is one of the most common complications. We tried to reduce the rate of that complication by using an air endotamponade.The following study is a retrospective comparison of 2 patient groups both after pars plana vitrectomy due to proliferative diabetic retinopathy. Group 1 was managed with air as endotamponade (n = 52, mean age 61.2 years), group 2 without any endotamponade (n = 40, mean age 59.4 years). Classification of the proliferative diabetic retinopathy as described by Kroll et al. [5] in both groups: 23 and 29 patients with stage A resp., 24 and 10 patients with stage B resp., 5 and 1 patient with stage C respectively.77% of group 1 patients had an increase os vision by mean of 4.8 vision steps, in 70% of the group 2 patients vision increased by mean of 7.2 vision steps. Complications in both groups as follows: Rebleeding within 14 days 15% vs. 33%, development of secondary glaucoma in 9.6% and 17.5% resp., revitrectomy within 14 days were necessary in 3.8% resp. 2.5% of the patients, later revitrectomy in 13.5% vs. 42.5% of all patients.Air endotamponade turned out to be appropriate to reduce the rate of postoperative vitreous rebleeding after pars plana vitrectomy due to proliferative diabetic retinopathy. We found no increase of secondary glaucoma or cataract.