Chagas’ disease caused by “Trypanosoma cruzi” (T. cruzi), is well recognized as an opportunistic infection in the setting of HIV / AIDS. More patients with Chagas’ disease, live in countries of Central and South America, That’s why, it is also called “American Trypanosomiasis “. T. cruzi is mainly transmitted by vectors (“Triatoma infestans” in Argentina) specially in the “endemic american area” and secondarily, by blood transfusion, not only in America, but also in the rest of the world. Many people have migrated from the endemic area of America to others countries around the world. Perhaps, some of them were asyntomatic “chagasic” patients and may have transmitted T. cruzi by blood transfusions in those non-endemic areas.. So that, Chagas’ disease should be considered nowadays, as a “global pathology”. In severely inmunocompromissed patients with AIDS, chronic Chagas’ disease may have reactivated, affecting central nervous system (CNS) with brain mass lesions (called “chagomas”), similar to others necrotizing encephalitis like Toxoplasmosis.. We report a 32 year-old woman assisted in the Rawson Hospital of Córdoba City (Argentina), with AIDS and reactivation of Chagas’ disease. Patient coming from Catamarca (north-western region of Argentina) with severe headache, unisocoria, desorientation in time and space, fine tremor, nistagmus, clonus, hiperreflexia and fascial-braquial-crural hemiparesia. Patient was afebrile and the rest of physical examination was normal. She had low count of CD4 cells and high HIV-viral load. Magnetic resonance imagin (MRI) showed: several enhanced rounded lesions surrounded by edema along the whole brain. Treatment with sulfadiacina + Pyrimethamine and Dexametasone, for a presuntive cerebral toxoplasmosis was implemented but, patient did not improve. So, cerebral biopsie was performed and it showed: intra and extracellular “ AMASTIGOTES” of T. cruzi..Treatment with Benznidazol was prescribed, but in a few days, patient died.