Retinitis is a very common disease in the eye, which is divided into two big categories:infectious and non infectious. Infectious retinitis is common in immunosuppressed patients and they are divided according to the type of opportunistic organism. They are viral,protozoal,bacterial and fungal. This retinitis in immunosuppressed patient has a poor prognosis except in some cases that drugs play a very important role in control the case such as intravitral ganciclovir implant in treatment of CMV retinitis.There is decrease the incidence of retinitis to 55%. Early diagnosis and treatment for retinitis is the best for more possibility to regress the disease.