Enzyme-linked immunosorbent assay (ELISA) was compared with haemagglutination inhibition (HI) test for determination of anti-dengue and anti-Japanese encephalitis (JE) antibodies in paired sera from 168 patients with clinical diagnosis of dengue haemorrhagic fever (DHF) in Rangoon, Burma. Using paired sera, HI serology gave 60.7% positive results. IgG ELISA antibodies showed cross reaction between dengue and JE, and also not so efficient to detect significant antibody rise. By IgM capture ELISA 60.5% positive results was obtained using acute sera and dengue 4 antigen alone for diagnosis. When paired sera and all 4 types of dengue were used, 82.1% positive results were obtained by the IgM-capture ELISA, and none of the test sera had diagnostic levels of IgM-ELISA antibodies against JE. The results showed that IgM capture ELISA is a useful method for rapid diagnosis of dengue infections and has advantages over HI in terms of its diagnostic efficiency even by a single serum specimen, rapidity, simplicity and differential diagnosis with other related flavivirus infections like JE.