Thymectomy has played a central role in the management of myasthenia gravis. Although both the etiology of myasthenia gravis and the reason for improvement after thymectomy remain incompletely explained, complete removal of the thymus is the logical goal of surgical treatment for this disease.From April 1989 to June 1994, maximal thymectomy was performed for 19 cases of myasthenia gravis at Chonnam National University Hospital. The results were as follows:1.Among the 19 cases, male-to-female ratio was 1:1.4, the age ranged 13 years to 71 years, and a diphasic presentation appeared with a peak in young females and a second peak in elderly males;2.Five cases were classified by modified Osserman`s classification as Group I and Group IIa and 14 cases as Group IIb and Group IIc; 3.Histologic examination of the excised thymus glands revealed normality in 5 cases [26% , thymic hyperplasia in 4 [21% , benign thymoma in 8 [42% , and malignant thymoma in 2 [11% ;4.There was no operative mortalities but two deaths occurred during the follow-up periods due to myasthenic crisis and other causes;5.The clinical improvement and the complete remission rates were 85% and 32%, respectively;6.The clinical improvement and the complete remission rates were not so good in patients with thymomas, beeing 70% and 20%, respectively; and 7.Young women with hyperplasia of the thymic tissue tended to show the best response to thymectomy.