Objective: The frequency of thyroid nodules accompanying Graves' disease and the risk of thyroid cancer in presence of accompanying nodules are controversial. The aim of this study was to evaluate the frequency of thyroid nodules and the risk of thyroid cancer in patients operated because of graves' disease. Subjects and methods: Five hundred and twenty-six patients in whom thyroidectomy was performed because of Graves' disease between 2006 and 2013 were evaluated retrospectively. Patients who had received radioactive iodine treatment and external irradiation treatment in the neck region and who had had thyroid surgery previously were not included in the study. Results: While accompanying thyroid nodule was present in 177 (33.6%) of 526 Graves' patients, thyroid nodule was absent in 349 (66.4%) patients. Forty-two (8%) patients had thyroid cancer. The rate of thyroid cancer was 5.4% (n = 19) in the Graves' patients who had no nodule, whereas it was 13% (n = 23) in the patients who had nodule. The risk of thyroid cancer increased significantly in presence of nodule (p = 0.003). Three patients had recurrence. No patient had distant metastasis. No patient died during the follow-up period. Conclusions: Especially Graves' patients who have been decided to be followed up should be evaluated carefully during the follow-up in terms of thyroid cancer which may accompany. Arq Bras Endocrinol Metab. 2014;58(9):933-8 Keywords Graves' disease; thyroid nodules; thyroid cancer RESUMO Objetivo: A frequência da ocorrência de nódulos tiroidianos acompanhando a doença de Graves e o risco de câncer de tiroide na presença desses nódulos é controversa. O objetivo deste estudo foi avaliar a frequência de nódulos tiroidianos e o risco de câncer de tiroide em pacientes operados por doença de Graves. Sujeitos e métodos: Quinhentos e vinte e seis pacientes anteriormente submetidos à tiroidectomia por doença de Graves entre 2006 e 2013 foram avaliados retrospectivamente. Os pacientes que receberam tratamento com iodo radioativo e irradiação externa da região do pescoço e que anteriormente passaram por cirurgia de tiroide não foram incluídos no estudo. Resultados: Enquanto os nódulos de tiroide se apresentaram em 177 (33,6%) dos 526 pacientes com doença de Graves, eles estiveram ausentes em 349 (66,4%) pacientes. Um total de 42 (8%) dos pacientes teve câncer de tiroide. A ocorrência de câncer de tiroide foi 5,4% (n = 19) nos pacientes com doença de Graves que não apresentaram nódulos, e 13% (n = 23) nos pacientes com nódulos. O risco de câncer de tiroide aumentou significativamente na presença de nódulos (p = 0,003). Três pacientes apresentaram recidivas. Nenhum paciente apresentou metástase distante e nenhum paciente veio a óbito durante o período de acompanhamento. Conclusões: Pacientes com doença de Graves devem ser avaliados cuidadosamente no acompanhamento para a possível ocorrência de câncer de tiroide. Arq Bras Endocrinol Metab. 2014;58(9):933-8 Descritores Doença de Graves; nódulos tiroidianos; câncer de tiroide