The effects of treatment modality for Graves' disease (GD) were studied with respect to long-term quality of life and present health status. A total of 179 patients with GD were randomized during the period 1983-1990 for treatment with antithyroid drugs, radioiodine, or surgery. A 36-item Short Form Health Status Survey questionnaire and specific questions for GD were sent to patients 14-21 years after randomization. Present medical records, and clinical and laboratory status were recorded. No major significant differences in quality of life among the three treatments were observed. Compared to a large Swedish reference group, all treatment groups had significantly lower scores for vitality (p < 0.05). The Mental Component Summary was lower for both the young medical, young surgical, and the older medical group (p < 0.05). Radioiodine-treated patients had a lower General Health score. Young medical patients (<35 years) had lower Mental Health scores (p < 0.05). There was also a strong trend, which barely met statistically significance, for older surgical and radioiodine groups for lower Mental Component Summary. GD patients have, compared with a large Swedish reference population, diminished vital and mental quality of life aspects even many years after treatment. The quality-of-life scores were not different among the three treatment modalities.