Abstract: OBJECTIVE To investigate the effect of isoflurane and etomidate on serum levels of Bcl-2 in patients with myasthenia gravis thymectomy. METHODS Forty patients with myasthenia gravis thymectomy were randomly divided into isoflurane group and etomidate group. The levels of Bcl-2 were measured at preoperative and postoperative with ELISA method. RESULTS The serum Bcl-2 levels postoperative were lower than preoperative in isoflurane group (P<0.01). The serum Bcl-2 levels postoperative were higher than preoperative in etomidate group (P<0.01). There was no significant difference of Bcl-2 serum levels between the two groups before surgery (P>0.05). The Bcl-2 serum levels in etomidate group were higher than isoflurane group postoperative (P<0.01). CONCLUSION Isoflurane can reduce the serum levels of Bcl-2 during thymectomy, while etomidate increases the level of Bcl-2. Isoflurane is more suitable than etomidate for patients with thymectomy.