: A 66-year-old woman with acromegaly and diabetes mellitus as well as primary hyperthyroidism is described. Serum GH Levels were inappprpriately high.MRI revealed an enlarged sella turcica with intrasellar mass. Her HbAlc was 12.2% and fasting blood glucose 8.89 mmol/l. Thyroid hormone levels in serum and thyroidal radioiodine uptake values were elevated, while TSH measurements in serum were low. Anti TPO antibodies were negative, TSH receptor antibodies were normal. Thyrotoxicosis as the first presenting illness in acromegaly was particulary uncommon. An ultrasound thyroid scan showed a multinodular goiter. Histology of the pituitary lesion showed a typical eosinophilic adenoma which only secreted GH when tested with specific immunostain. Post-operatively, the patient's clinical conditions improved, however, secondary hypoadrenalism appeared.