Abstract: Using human spermatozoa nuclei treated with chymotrypsin and trypsin as antigen substrate, the anti-DNA antibody was determined with indirect immunofluorescence test and compared in matched pairs with conventional methods.It was found that with 1/10 dilution of serum as limit, the result of this method(ESN-IFT) corresponded to that of conventional methods.The titer of ESNIFT reflected the quantitative change as determined with RIA.Tlie sensitivity and specificity of this test was just between RIA and CL-IFT.Because the ESN-IFT has the advantage of simplicity and easiness,so it has some practical significance.