Background: Toxoplasmosis is a zoonotic disease, worldwide distribution caused by an obligaternintracellular coccidian parasite, known as Toxoplasma gondii. T. gondii can lead to seriousrndiseases in immuno compromised patients such as HIV/AIDS patients. In most cases, centralrnnervous system involvement can lead to encephalitis, which is one of the most important reasonsrnof death among patients with HIV due to reactivation of tissue cysts that remained latent after thernprimary infection.rnObjective: This study was conducted to assess the Sero burden of Toxoplasma gondii infectionrnand to identify associated risk factors among HIV/AIDS patients in Armed Forces Referral &rnTeaching Hospital, Addis Ababa, Ethiopia.rnMethods: A cross sectional study was conducted in Armed Forces Referral & TeachingrnHospital, Addis Ababa, Ethiopia from March toMay2016. The sampling method was based onrnconvenience sampling. After getting an informed consent, pretested questionnaire were used torngather socio demographic information and data on factors predisposing to T. gondii infection.rnSerum samples from each volunteering patients were screened for the presence of anti- T.gondiirnIgG & IgM antibodies by using ELISA test kit (CTKBIOTECH, USA). Data were entered andrnanalyzed using SPSS version 15.0.The chi-square test was used to determine the associationrnbetween variables. P values were determined and taken as a level of significance when it wasrnfound less than 0.05.rnResults: The study recruited a total of 174 HIV/AIDS patients, 99 (56.9%) were males and 75rn(43.1%) were females. The study also included age strata ranging from 18 to 68years. Most ofrnthe sampled subjects were found in the age group of 31 to 40 years. About 154 (88.5%) werernseropositive for anti-T. gondii IgG antibody and 3 (1.7%) were seropositivity for anti- T. gondiirnIgM antibodies. None was positive for IgM antibody alone. Of all the variables included in thernstudy, only presence of cat depicted association with sero-burden of anti-Toxoplasma gondii IgGrnantibody (p=0.038).rnConclusion: This study revealed high sero burden of chronic toxoplasmosis in HIV/AIDSrnpatients. HIV/ AIDS patients having domestic cat at their home were at higher risk of T. gondiirninfection. It would be important to increase public awareness about different routes ofrntransmission of T. gondii. Besides, routine screening for Toxoplasma should be undertaken forrnall HIV-infected patients to minimize complication related to reactivation.