A recent publication reported a high prevalence of double-stranded DNA antibodies quantitated by RIA in patients with Graves' disease. We, therefore, measured antibodies to a variety of nuclear antigens in 20 patients with Graves' disease, most of whom where hyperthyroid. Fluorescent antinuclear antibody tests using HEp-2 cells as substrate were positive in serum of 15 of the 20 patients but in only 2 of 20 normal subjects. DNA binding, determined by RIA, was increased in 12 of 18 patients with Graves' disease. However, a more specific indirect immunofluorescence assay for antibodies to double-stranded DNA using Crithidia luciliae was negative in all 20 patients. Furthermore, antibodies to single-stranded DNA, measured by counterimmunoelectrophoresis, and ribonucleoprotein and Sm antigens, measured by double diffusion in agar, were undetectable in all patients tested. These results demonstrate a high frequency of antinuclear antibody in patients with Graves' disease. The presence of antibodies to double-stranded DNA was not confirmed when assayed by the highly specific and sensitive Crithidia luciliae method, suggesting nonantibody DNA binding in the DNA RIA.