Aims-To study the long term results of vitrectomy and silicone oil injection in AIDS patients with retinal detachment due to viral retinitis. Methods-A consecutive series of 83 eyes in 75 AIDS patients who were treated with vitrectomy and silicone oil for retinal detachment due to viral retinitis was studied prospectively and followed until the last patient in the series had died. Results-Median postoperative survival was 6 months, but 20% of patients survived 12 months or more. Whereas best corrected visual acuity was 20/100 or better in over half the patients 1-2 months after operation, there was a distressing decrease in acuity by 6 months, owing to a variety of factors. Patients operated on before macular detachment did not have significantly better postoperative vision than those operated within a week after macular detachment. Almost all patients who had already lost vision in the fellow eye and many who had cytomegalovirus retinitis in the fellow eye with retention of good vision had their quality of life improved by the surgery in that the operated eye eventually became the better seeing eye. In no patient whose fellow eye was normal and free of retinitis, however, did the operated eye ever become the better eye. Conclusions-Although the majority of patients recovered macular vision in the first 1-2 months after operation, there was a gradual decline in acuity thereafter, sometimes without obvious cause. The results of this series suggest that it may be reasonable to postpone surgery until the macula detaches and that patients whose fellow eye is free of retinitis with normal vision are unlikely to have their quality of life improved significantly by the surgery.