Objective\ud Thyroid status in the months following radioiodine treatment for Graves’ disease can be unstable.Our objective was to quantify frequency of abnormal thyroid function post-radioiodine and compare effectiveness of common management strategies.\ud \ud Design\ud Retrospective, multi-centre, observational study.\ud \ud Patients\ud Adult patients with Graves’ disease treated with radioiodine with 12 months’ follow-up.\ud \ud Measurements\ud Euthyroidism was defined as both serum thyrotropin (TSH) and free thyroxine (FT4) within their reference ranges or, when only one was available, it was within its reference range; hypothyroidism as TSH ≥ 10 mu/L, or subnormal FT4 regardless of TSH; hyperthyroidism as TSH below and FT4 above their reference ranges; dysthyroidism as the sum of hypo- and hyperthyroidism; subclinical hypothyroidism as normal FT4 and TSH between the upper limit of normal and