OBJECTIVES: Myasthenia Gravis (MG) is an auto immune disease of neuromuscular junction, which influences patients’ quality of life (QoL). Studies had showed MG patients with poor QoL, but there is no data in Chinese MG patients. METHODS: Consecutive MG patients are enrolled in three hospitals in Shenyang, China, from July, 2008 to June, 2010. Patients (14≤age≤75 years) with class ‡T, ‡Ua, or ‡Ub MG according to Osserman’s classification are enrolled, and are separated into Ocular, Mild and Moderate groups. Familial MG, congenital MG and drug-induced MG are excluded. QoL is assessed by the SF-36 (rang: 0-100); severity of the disease is assessed by Chinese Score for MG (CSMG rang 12-60; higher scores worse weakness). Differences are tested using ANOVA and Kruskall-Wallis as appropriate. RESULTS: Analysis is based on 248 patients (male 110, 44%; age:46±18 year), of whom 27%, 35% and 38% classified into Ocular, Mild and Moderated groups respectively. The disease history is 47±64 months (median 24). Fifty-nine patients have at least one comorbidity, and 71 with thymic hyperplasia, and 49 thymectomy. There is no significant difference in demographic characteristics among three groups (P>0.05), and no difference in disease history, comorbidity and treatment either. Ocular group has better QoL than Mild and Moderated groups: 64, 57, 51 for each group respectively (P=0.000), and better weakness in CSMG scores: 21, 23, 26 respectively (P=0.000). Significant differences is found in all the subscales of SF-36 among groups (P<0.05), except for general health (P=0.054), social functioning (P=0.490), and role-emotional (P=0.104). CONCLUSIONS: Our study reveals that Chinese MG patients have poor QoL, and Ocular MG patients have better QoL than those who are Mild and Moderate MG, and QoL is influence by the degree of muscle weakness.