In the second case, hypothyroidism developed in only 7 months after diagnosis of Graves’ hyperthyroidism was established. To our knowledge, clinical manifestation of Hashimoto’s thyroiditis may take place through three stages, i.e. the early stage, second and final stage. The early stage has hyperthyroidism state as there is excessive thyroid hormone secretion into circulation due to partial destruction thyroid cells. In the second stage, the thyroid has normal function (euthyroid) and the final stage includes hypothyroidism. Hashimoto’s hyperthyroidism usually has mild and transient hyperthyroidism; thus, most patients in hyperthyroid state remain unrecognized. In this patient, the clinical manifestations and very high level of FT4 suggesting Graves’ hyperthyroidism; however, there was no TRAb results to confirm such a diagnosis. Nevertheless, in addition to high TSHs level, positive microsomal antibody and thyroglobulin antibody as well as the result of histopathological examination have provided evidences for Hashimoto’s thyroiditis.