There is no agreement wither thyroid disease is a common feature of progressive systemic sclerosis (PSS). We evaluated 28 patients with proven PSS with determinations of T3, T4, TSH and Tg as well as antimicrosomal autoantibodies. Radioactive I uptake, thyroid scintigraphy, TRH test and fine needle biopsy were performed in selected patients. Twelve (43%) patients had clinical or laboratory evidence of thyroid dysfunction. Four patients had euthyroid goiter, 3 had evidence of autoimmune disease, 2 had chronic Hashimoto's thyroiditis, 1 was hypothyroid, 1 hyperthyroid and one has subacute thyroiditis. The CREST variant of PSS was most commonly associated with thyroid pathology. Our results indicated that thyroid disease is frequently associated to PSS. A complete clinical and laboratory evaluation is needed to confirm its presence.