After the diagnosis of hyperthyroidism in patients, there is a search for a precise diagnosis as well as the prescription of a treatment according to its etiology. However a listing of symptoms and signs, present at the time of diagnosis, is seldom established. The weight history of the patient is almost always lacking in the medical records of hyperthyroid patient. By the time the patient has been treated after a few weeks or months, he often complains of weight gain. Thereafter the knowledge of the variations of the weight at the time of diagnosis will allow not only to get some insight in the psycho-social setting and the patient's habits, but also to deal with the critical time of the disappearance of hypermetabolism, linked to the hyperthyroid state, which could promote a weight gain.