Trypanosoma cruzi proteins from epimastigote membranes, herein referred as antigens, have been used for the construction of an amperometric immunosensor for serological diagnosis of Chagas’ disease. The proteins used had a molecular mass ranging from 30 to 100kDa. The gold electrode was treated with cysteamine and glutaraldehyde prior to antigen immobilization. Antibodies present in the serum of patients with Chagas’ disease were captured by the immobilized antigens and the affinity interaction was monitored by chronoamperometry at a potential of −400mV (versus Ag pseudo-reference electrode) using peroxidase-labeled IgG conjugate and hydrogen peroxide, iodide substrate. The incubation time to allow maximum antigen–antibody and antibody–peroxidase-labeled IgG interactions was 20min with a reactivity threshold at −0.104μA.