Vitreous haemorrhage is a serious complication of proliferative diabetic retinopathy : it provides evidence of the severity of at proliferative retinopathy at stake and precludes laser photocoagulation. In some cases of moderate vitreous haemorrhage, panretinal photocoagulation remains possible especially using longer wavelengths such as krypton red; cryotherapy under ophthalmoscopic control may be an alternative to panretinal photocoagulation. Developpement of pars plana vitrectomy, however, has been the main break the rough in the management of severe vitreous haemorrhage. Pars plana vitrectomy was first reserved to massive, long-standing vitreous haemorrhage; improvements in instrumentation and techniques, as well as observations of the favourable effect of vitrectomy on the progression of proliferative retinopathy led to enlarger indications for pars plana vitrectomy. Beyond severity and duration of visual loss, main arguments for pars plana vitrectomy are bilaterality, lack of previous panretinal photocoagulation, iris neovascularization, Type 1 diabetes, and severity of fibrovascular proliferation.