The objective of this report is to describe treatment outcomes over a four-year period of patients with acute Chagas disease in the Amazon region of Brazil. An outbreak of Chagas disease in a low-income district of urban Belém, in September 2000, affected 11 people simultaneously, indicating the likelihood of indirect, oral transmission of Trypanosoma cruzi. Prior to treatment, patients underwent physical and clinical tests; blood samples were processed with immunofluorescence assay (IFA) and quantitative buffy coat (QBC). Following treatment with benznidazole, parasitological and serologic tests (artificial xenodiagnosis and blood culture for T. cruzi), electrocardiogram, and echocardiogram were administered at intervals over a four-year period. Four years after treatment for acute Chagas disease, all patients presented with negative parasitological tests and persistent IgG anti-T. cruzi antibodies with lowered titers; three patients presented electrocardiogram abnormalities consistent with chronic Chagas disease or sequel of acute disease. The satisfactory response to treatment and relevance of serial parasitological examinations of patients with acute Chagas disease are discussed.