Abstract: Sera from 453 persons, including 98 patients with systemic lupus erythematosus(SLE), 165 patieats with other connective tissue diseases sad 61 miscellaneous diseases as well as 129 normal control. were determined by two methods-Trypanosoma Equiperdum immunofluorescent(TE-IF)method and Farr immunoprecipitatioa assay for anti-double stranded DNA antibodies. The results showed that antidsDNA antibodies are highly specific for SLE. The specificity is influenced, by differeat methods. In comparison with Farr assay, the TE-IF method is better not-oaly is specificity but also in simplicity of performance,reliability, constancy of results and abseace of falsepositive reactions. It is of value in-diagnosisrand follow-up of SLE.