Myasthenia gravis (MG) is an autoimmune disorder affecting neuro-muscular transmission. Although MG patients suffering from their muscle weakness and its related psychological symptoms, few studies have been done to measure the psychological burden quantitatively imposed by MG. Therefore, we sought to assess several aspects of psychological distress of MG patients quantitatively and compare them to normal healthy controls in the 19-year-old military candidates.In Korea, a conscription system has been adopted, wherein all men 19 years old and over have military duty. Before joining the army, all men undergo evaluations of physical and psychological status by clinicians from all departments of the Military Manpower Administration (MMA). Among them, we reviewed 988, 720 medical records of Korean military candidates aged 19 years from February 2010 to January 2013. MG was diagnosed by neurologists based on the results of acetylcholine receptor antibody test, repetitive nerve stimulation test, or clinical manifestations in the hospitals and MMAs. Psychological distress was evaluated using Korean Military Multiphasic Personality Inventory (MPI). We controlled the variables for age, sex, and race-ethnicity (19-year-old men in Korea). MG patients reported significantly lower level of faking good scale (t = 2.564, p = 0.012) among validity scales and significantly higher level of somatization scale (t = -2.340, p = 0.021) among neurosis scales and showed increasing tendency of anxiety scale(t = -1.826, p = 0.070), with no statistical significance. We estimated psychological burden of MG in the 19-year-old military candidates in Korea. Less faking good attitude, higher level of somatization scale and increasing tendency of anxiety scale of MG patients may represent psychological distress burdened by MG. It is not yet apparent whether psychological distress is related to the illness-related symptoms or psychiatric vegetative signs.