The parasitic protozoan Trypanosoma cruzi infects an estimated 16 million individuals in Latin America. In a variable proportion of patients, this infection can result in a life-threatening cardiac or digestive pathology recognized as Chagas disease. In the majority of cases, the parasitemic phase of infection is transient and often goes unnoticed against the high background of endemic diseases present in the low-income groups usually affected by T. cruzi infection. Consequently, diagnosis of the infection by direct microscopic examination is rarely possible; therefore, routine serologic procedures as well as modern molecular techniques provide the most sensitive indicators of human infection.