Myasthenia gravis is an autoimmune disease in which the thymus gland is thought to play a central role in the pathogenesis. Thymectomy is now standard therapy, and improvements in surgical techniques, anesthesia, and respiratory care and the use of plasmapheresis have markedly reduced the operative morbidity. We experienced 7 myasthenia gravis with maximal thymectomy from November 1989. As compared with the results of previous classic transsternal thymectomy group the 25 patients who were operated from June 1979 to December 1991[Group B], excellent surgical result was obtained in maximal thymectomy group[Group A]. During follow-up period that ranged from a month to 10.7 years[mean 2 years], the remission rate for the entire group was 15.6 percent and an additional 71.9 percent had improvement[87.5 percent benefited]. In Group A, the remission rate was 42.9 percent with 100 percent of the patients benefiting from operations. But in Group B, 8 percent had remission and a total of 80 percent benefited. In both Groups, there was no operative mortality but there was one case`s mortality in Group B during follow-up period.