Silicone oil injection in conjunction with pars plana vitrectomy was carried out by five surgeons in 415 consecutive patients using the same surgical equipment, the same surgical techniques and the same highly purified silicone oil (viscosity, 5000 mPa.s). Indications for silicone oil injection after vitrectomy included advanced stages of proliferative vitreoretinopathy following rhegmatogenous retinal detachment (49%), severe proliferative diabetic retinopathy (38%), and proliferative vitreoretinopathy following retinal detachment due to ocular trauma (13%). Postoperative complications were noted in a 6- to 30-month follow-up period. Cataractous changes of varying degree were seen in all phakic eyes. Silicone oil entered the anterior chamber in 6% of all phakic and pseudophakic eyes. Subretinal silicone oil was noted in 4%. Other complications associated with the use of intravitreal silicone oil included biomicroscopically visible silicone oil emulsification (0.7%), keratopathy (5.5%), glaucoma (6%), closure of the inferior iridectomy (6%), and reproliferation of epiretinal and subretinal fibrous membranes (40%). We anticipate that the physico-chemical characteristics of the highly purified silicone oil (viscosity, 5000 mPa.s) and the routine performance of an inferior iridectomy in all aphakic eyes had a positive impact on the low incidence of silicone-oil-related complications such as emulsification, keratopathy and secondary glaucoma.