Junín arenavirus is the etiologic agent of Argentine hemorrhagic fever. Due to its morbidity and high mortality rate in untreated cases, this endemic disease is of mandatory report in Argentina. Secure and accurate diagnostic methods are needed for the epidemiological surveillance of the disease. Current assays rely on antigens prepared from lysates of virus infected mammalian cells. The bio-safety issue related to the manipulation of large quantities of virus restricts such antigen production to laboratories with the appropriate containment facilities. In this report, we describe the development of an enzyme linked immunosorbent assay for the etiologic confirmation of the disease, based on recombinant antigens expressed in insect cells. Eight different variables of the assay were optimized with the Taguchi approach for experimental design (L18 design, seven three-level factors and one two-level factor). The area under the receiver operating characteristics (ROC) curve was 0.966, showing the high accuracy of the test discriminating positive from negative samples. Taking into account the biosafety benefits, the high yields of antigen in cell culture, and the general performance of the assay, it is expected that it will be a useful alternative to the current ELISA for the detection of antibodies in sera from convalescent patients. J. Med. Virol. 80:2127–2133, 2008. © 2008 Wiley-Liss, Inc.