A 53-year old female patient, who presented with retrosternal pain, which could be ascribed to reflux oesophagitis and gastritis, furthermore stated recurrent palpitations, sweating and the feeling of uneasiness. In routine laboratory investigation hyperthyroidism and hypercalcaemia were detected. Further testing revealed elevated TSH receptor antibodies and a parathyroid hormone level within the normal range. Scintigraphically a homogeneous, but increased uptake was found. In ultrasonography guided fine needle aspiration biopsy of a nodule parathyroid hormone was verifiable by immunochemical means.Under thyrostatic treatment with carbimazole the patient became euthyroid, simultaneous a decrease of serum calcium levels could be observed. Parathyroid hormone level remained in normal range. After confirmation of Graves’ disease and adenoma of the parathyroid gland parathyroidectomy in combination with near total resection of the thyroid gland was performed. In conclusions concomitant Graves’ disease and primary hyperparathyroidism is rare, but should be considered in case of persisting hypercalcaemia after the patient became euthyroid again, when parathyroid hormone level is in normal range or elevated. Thus a potentially required second operation can be avoided. By ultrasonography guided fine needle aspiration biopsy and immunochemical processing adenomas of parathyroid glands can be localized preoperatively.