We have surgically treated eleven children (seven boys and four girls) suffering from myasthenia gravis (MG) from October, 1991 to June, 1995-The ages of the patients varied from 5 to 12 years. The duration of the first myasthenic symptom to thymectomy ranged from 2 to 96 months. According to Osserman classification of clinical stage of MG.the 11 patients were graded Ⅰ (ocular signs and symptoms only) 4 cases; ⅡA (mild generalized weakness) 5 cases; ⅡB (moderate generalized weakness) 2 cases. The patients were preoperatively given enough anti-cholinesterase agents and made in their best condition. The operative approach are as follows:we all made the mid-sternal incision,thus increased the likelihood of obtaining total thymectomy including anterior mediastinal fat in order to avoid thymokesis of ectopic foci of thymic tissue. The removed thymus ranged from 22 to 41.5 grams and averaged 35 grams. By pathological examination,3 patients were, thymopathy (lymphocyte type) and others,thymic hyperplasia. Po We have surgically treated eleven children (seven boys and four girls) suffering from myasthenia gravis (MG) from October, 1991 to June, 1995-The ages of the patients varied from 5 to 12 years. The duration of the first myasthenic symptom to thymectomy According to Osserman classification of clinical stage of MG. The 11 patients were graded Ⅰ (ocular signs and symptoms only) 4 cases; ⅡA (mild generalized weakness) 5 cases; ⅡB (moderate generalized weakness) 2 cases The patients were preoperatively given enough anti-cholinesterase agents and made in their best condition. We all made the mid-sternal incision, thus increasing the likelihood of obtaining total thymectomy including anterior mediastinal fat in order to avoid Thymokesis of ectopic foci of thymic tissue. The removal of thymus ranged from 22 to 41.5 grams and averaged 35 grams. By pathological examination, 3 patients were, thymopathy (lymphocyte type) and others, thymic hyperplasia. Po