Myasthenia gravis is a neuromuscular, autoimmune, and acquired disturbance characterized by weakness and fatigue of skeletal muscles. During the past two decades, remarkable progress has been made in the understanding of myasthenia gravis, and the new knowledge has been applied directly to the clinical diagnosis and treatment of this formerly severe disease. Myasthenia gravis is undoubtedly the most thoroughly understood of all human autoimmune diseases and has served as a model for the elucidation of mechanisms underlying other autoimmune disorders. In this review we mention the most important physiopathological aspects and its application in the clinic practice.