Myasthenia gravis is a disease that affects the neuromuscular junction causing abnormal weakness, fatigue, and muscle decay. Loss or dysfunction of acetylcholine receptors occurs mostly due to the presence of antibodies to nicotinic acetylcholine receptors (NAChR). The thymus and thymoma have a special role in the pathophysiology of myasthenia gravis due to the role of the thymus in the maturation and distribution of lymphocytes where cross-reactivity and consequent autoimmunity to NAChR can occur. The most commonly used diagnostic method for myasthenia gravis is the measurement of antibody levels to NAChR which is a highly specific test for the diagnosis of myasthenia gravis. CT is the method of choice in the diagnosis of thymoma. Due to the importance of the thymus in the pathophysiology of myasthenia gravis the disease can be treated surgically, by removing the thymus. If there is thymoma present, to plan the operation, Masaoka and TNM classification are used. Methods that can be used to remove the thymus / thymoma are transsternal thymectomy, transcervical thymectomy, video-assisted thoracoscopic surgery (VATS) and robotic surgery. Some of the factors influencing the prognosis after thymectomy are age and sex, presence of thymoma, surgical technique, extent of resection and severity and duration of symptoms of myasthenia gravis. New methods of thymectomy are minimally invasive and with rapid recovery, and most patients show remission of the disease after removal of thymus.