Cigarette smoking is a well-recognized risk factor of Graves’ disease and, particularly, Graves’ ophthalmopathy. Hence, germline polymorphisms of detoxification genes and genes belonging to the major DNA repair/apoptosis pathways might have an important role in disease susceptibility. In addition, as some of these genes are regulated by thyroid hormones, they could affect the outcome of these patients. Our objective was to assess the influence of the GST, CYP and TP53 gene polymorphisms in the risk of Graves' disease and its outcome.