Chagas disease is a vector-borne parasitic infection affecting an estimated 6 million people worldwide. Very few people have been able to access antiparasitic treatment for the disease, and about 20% of those who do initiate treatment are unable to complete it due to the long duration (2 months) and side effects associated with the current regimen. Benznidazole is one of only two drugs with proven efficacy against Trypanosoma cruzi, the parasite that causes the disease. An earlier Phase 2 clinical trial, BENDITA, indicated 89% of 30 patients treated with a shorter (2-week) regimen of benznidazole maintained sustained parasite clearance after 12 months of follow-up, with no discontinuations of treatment due to side effects. The current study will evaluate shorter treatment regimens with benznidazole in a Phase III clinical trial. NuestroBen will assess the efficacy and safety of 2-week and 4-week regimens of BZN (300 mg daily), compared to the standard treatment of BZN 300 mg daily for 8 weeks, in terms of reducing and eliminating the T. cruzi parasite in adults in the chronic phase of Chagas disease with the indeterminate form or mild cardiac progression. Efficacy will be measured through conversion from positive to negative parasitaemia according to the results of qualitative PCR tests from the end of treatment, and up to 12 months of follow-up from the end of treatment. Safety will be compared according to the frequency and severity of adverse events. Patients adherence to treatment in each study arm will also be described.