Abstract: A follow-up study of 9 patients with systemic lupus erythematosus(SLE)has been made through a serial clinical and Iabofatory investigations, It showed that the titers of antinuclear antibodies (ANA)and anti-ds-DNA antibodies was determined by Trypanosoma equiperdum indirect immunofluor-escent method(TE-IF)correlated closely with the activity of SLE, During the active stage the titers remained high, and during remission they became low or even aegative.The clinical exacerbation was preceeded by a steady rise of the titer, A sustained high titer may mean inadequacy of treatment and a premonition of developing nephrotic syndrome, Changes in the titers of ANA and anti-ds-DNA antibodies were similar, but the former were comparatively slower. Administration of large doses of corticosteroid caused a rapid dr op of the titer of anti-ds-DNA antibodies,The result of correlational analysis showed positive correlation between TE-IF and Farr assay(active stage; r=0.6833, P<0.05).Serial determinations of anti-ds-DNA antibodies and ANA by TE-IF at a regular interval are considered to be of value in the treatment and surveillance of SLE.