Chagas'disease has a great epidemiological relevance. Most of infected children are asymptomatics, with low mortality rate. The most frequent clinical findings are hepatomegaly and splenomegaly Parasitological methods: fresh smears, microStrout and Hemoculture, sequentially performed, detect the parasite in almost 100% of infected children. The gold standard for immunodiagnosis are serological curves, due to the interference of maternal IgG. Infected children maintain their antibody levels , whereas non infected became negatives. IgM test show false positive and false negative results. In children acutely infected during the first year of life and in cases of congenital infection, we observed high serum levels of soluble receptors of TNFalpha, IL-2 and sCD8, with significantly post treatment decrease. In a prospective 30 years research, we observed high therapeutic efficacy when children were treated before 3 years of life with benznidazol or nifurtimox, with good clinical evolution, together with parasitological and serological negativization.