A 40 years old, married Govt. servant from Sadar upazila, Mymensingh was admitted in Mymensingh Medical College Hospital on 9(th) February, 2005 with the complaints of excessive sweating for 1 year, gradual loss of weight for 6 months, swelling in front of the neck for 1(1/2) months, and hoarseness of voice for 1 month. He was nervous, irritable, emotionally labile. Thyroid gland was symmetrically enlarged, firm in consistency with scalloped surface. Palms were warm and sweaty with fine tremor in outstretched hands. Lid lag, lid retraction and proptosis were the occular manifestations. All the reflexes were exaggerated. Radioactive iodine uptake showed enlarged gland with homogenously increased radiotracer concentration, ultrasonogram findings were enlarged gland with hypoechoic parenchyma with fibrous septa, T(3), T(4), TSH values were 6.56 nmol/L, 241.09 nmol/L and 0.14 mIU/L respectively. Thyroid microsomal antibody level was 32.87%. Thyroid FNAC findings were sheets of regular follicular cells, some large cells with granular basophilic cytoplasm, macrophages, a few inflammatory cells and giant cells. All the above findings were in favour of a diagnosis of hyperthyroid Graves' with Hashimoto's thyroiditis.