Objective To analyze the clinical features of 35 patients with myasthenia gravis (MG) associated with other autoimmune diseases (ADMG). Methods One hundred seventy MG patients were divided into 2 groups. One group included MG patients with autoimmune diseases ( n=35), and the other included MG patients without auto?immune diseases (NADMG, n=135). Clinical features such as gender, age of onset, types of MG, myasthenic crisis, thy?mus abnormalities, different therapies, ocular MG progressing to general MG, and relapse of MG within one year were compared between ADMG and NADMG. Results 85.7%ADMG patients were female which was higher compared with NADMG (P< 0.001); median age of onset was 40 years old (23~45 years old) in ADMG group which was younger than NADMG group. Ocular MG and thymic hyperplasia were more frequent in ADMG group than in NADMG group (45.7%vs. 24.4%, P=0.013;14.3%vs. 1.5%,P=0.001,respectively). Other clinical features such as myasthenic crisis, thymoma, different therapies, ocular MG progressing to general MG, and relapse of MG within one year were not signifi?cantly different between the two groups. In multivariate analysis, female (OR=4.76, 95% CI:1.64-13.77; P= 0.004), age of onset (OR=0.96, 95%CI:0.92-0.99;P=0.019), ocular MG (OR=3.10, 95%CI:1.30-7.41;P=0.011) and thy? mic hyperplasia(OR=16.26, 95%CI:2.22-119.11;P=0.006) were significantly different between the two groups. Con?clusions ADMG is more common in female patients with ocular MG and thymic hyperplasia.