This report describes the preparation and evaluation of an immunosensor based on chemical modification of gold surface with hantavirus (strain Araucaria) antigen/protein and the antibody detection by electrochemical analysis. The viral nucleoprotein was immobilized onto gold by SAM formation with 3-mercaptopropionic acid (MPA) followed by activation of the surface using N-(3-Dimethylaminopropyl)-N'-ethylcarbodiimide hydrochloride and N-Hydroxysuccinimide (EDC/NHS). Cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and quartz crystal microbalance (QCM) measurements were used for evaluation of each step involved in the construction of the proposed immunosensor. Several experimental conditions were studied and after optimization of immobilization parameters, the device showed good stability within 21 days and selectivity for a qualitative detection of specific antibody (IgG) directed against hantavirus Araucaria. The proposed sensor had shown a linear response for concentration varying between 0.400 and 300 mu g(-1) allowing its application in spiked serum samples for detection of specific antibody of hantavirus Araucaria based on a cutoff value. The immunosensor showed a sensitive response to the spiked samples and can be employed as an alternative for the qualitative diagnosis of hantavirus infections.