The diagnosis of dengue is an imperfect science. By 1983 we had sensitive isolation systems including arthropods and arthropod cell cultures, specific-and group-reactive monoclonal antibodies, and a rapid and sensitive immunoassay for IgM and IgG. Progress in the past 7 years encompasses the use of monocyte lines for primary isolation, a more rapid plaque reduction neutralization test with BHK-21 cells, labeled RNA probes to detect dengue-specific nucleic acid, and improved ELISA technology with specific synthetic and engineered antigens.