We report the case of a 42-Year-old woman with Recklinghausen disease (neurofibromatosis type 1) and Noonan syndrome who developed Graves' disease. Hyperthyroidism, which had existed for two Years without treatment, led to the discovery of neurofibromatosis type 1. The diagnosis of Graves' disease was confirmed by blood hormone levels, thyroid gland ultrasound, radioisotope scan and thyroid iodine uptake. Additional tests were carried out due to the patient's short stature and the presence of subcutaneous nodules. Hyperprolactinemia, bone defects (bone density testing), and abnormal MRI signals from the optic chiasma were disclosed. The diagnosis of Recklinghausen disease was proven histologically. The possible co-existence of neurofibromatosis type 1 and Noonan syndrome are discussed on the basis of this clinical case.