Most of the Graves' disease patients become euthyroid between 6 and 12 weeks after antithyroid drug use. Patients' compliance to the medication is essential for a successful therapy. The aims of the present study were to evaluate retrospectively the time spent to obtain clinical and hormonal euthyroidism, the costs of the clinical therapy in outpatients with Graves' disease and to compare them with the literature data. Eighty-two patients were selected between February/96 and November/97 and were followed-up until July/99. Forty-nine (59.8%) returned regularly until reaching euthyroidism, which occurred at a mean time of 24.8 weeks. Only 11 patients were euthyroid in 12 weeks. Sixteen patients were considered no compliant and the time necessary to reach the euthyroidism was significantly higher than that of the compliant group (37.3 vs. 18.7 weeks). The rate of the patients who abandoned follow-up before reaching the euthyroidism was 36,6%. The mean cost for 24.8 weeks treatment was R$248.72 versus R$151.68 for 12 weeks treatment, which is the period described in literature. In conclusion, our patients need more time to reach the euthyroidism than that usually described, which implies in 64% greater treatment cost. Poor compliance problems are the most important reason for this.