Abstract: Through antibody determination by ELISA of 68 sera from patients infected with B. malayi and 85 with W. bancrofti, it was found that 3 soluble antigens, adult worm and microfilariae of B. malayi and D. immitis adult antigen, possessed similar sensitivity. Adult worm antigen is considered to be the most promising in practical application, because it is relatively easy to obtain from artificially infected jirds and to prepare. The sensitivity of ELISA with adult worm antigen was 92.6% for malayan cases and 83.3% for bancroftian cases, its specificity being 98.8%.59 and 85 previous microfilaremia cases, who had becn treated with DEC or furapyrimidone 5 and 10 years ago were examined by ELISA, 30.5% and 16.5% of them remained positive, respectively. A seroepidemiological survey on filariasis by ELISA were carried out in 818 inhabitants living in 4 endemic villages, one of malayan and 3 of bancroftian types. The detection rate by ELISA was parallel to the microfilaraemia detection rate, the lowest being in children aged under 10 years.It is suggested that ELISA may be used as a means for auxiliary diagnosis and seroepidemiological survey of filariasis.