To report a case of cytomegalovirus (CMV) retinitis after intravitreal injection of triamcinolone acetonide (IVTA). A 77-year-old woman with macular edema due to central retinal vein occlusion (CRVO) developed peripheral retinitis 4 months after IVTA. A diagnostic anterior chamber paracentesis was performed to obtain DNA for a polymerase chain reaction (PCR) test for viral retinitis. The PCR test was positive for CMV DNA. Other tests for infective uveitis and immune competence were negative. Four months after presentation, gancyclovir was intravitreously injected a total of 5 times, and the retinitis resolved completely. CMV retinitis is a rare complication of local immunosuppression with IVTA. It can be managed with timely injection of intravitreal gancyclovir until recovery from local immunosuppression.