The vitrectomy operation is a new ophthalmic surgical procedure for the treatment of diabetic retinopathy. Since vitrectomy is a major intraocular surgical procedure with the potential for serious ocular complications, its use is reserved for certain advanced stages of proliferative diabetic retinopa thy (PDR) where safer alternative modes of therapy (e.g. photocoagulation) are ineffective. With this in mind one may consider vitrectomy surgery for two aspects of severe diabetic retinopathy: (a) severe vitreous hemorrhage, and (b) retinal detachment affecting or threatening central vision. This review article delineates the current techniques, indications, and results of vitrectomy surgery in the treatment of diabetic retinopathy. The natural history and a description of other modes of treatment of diabetic retinopathy introduce the discussion of the surgical procedure. Since new developments in this area of ophthalmic surgery are occurring rapidly, the potential of future advances is also discussed. The medical problems en countered in caring for the diabetic patient undergoing vitrectomy may be considerable, and therefore this aspect is also reviewed.