A summary of different kind of immune supressed hosts and the importance of Trypanosoma cruzi infection in this group of patients is presented. Then, most relevant aspects of immune compromised hostparasite interaction are analyzed such as the moment of acquiring the infection, immune compromise level, mechanisms of acquisition the infection and geographic region. Clinical features of primary infection and reactivation of infection in chronic Chagasic patients are described making especial emphasis in solid organ transplant and BMT. Chagas disease in AIDS patients is discussed including its treatment, follow up, monitoring the immune compromise level and prophylaxis.