Objective: To explore the postoperative clinical characteristics and outcomes of myasthenia gravis with and without thymoma. Methods: Two hundred and forty-three patients with myasthenia gravis (MG) surgically treated in our department from 1978 to 2003 were studied retrospectively. The clinical characteristics, complication, remissions and survival rates were compared between MG with and without thymoma. Results: The patients of MG with thymoma were significantly older (P＜0. 01), had shorter duration of symptom(P＜0.01), and higher myasthenia crisis rates after operation(P＜0.01) than those without thymoma. No difference of Osserman classification was found between the 2 groups. The complete remission rates and partial remission rates of MG with thymoma were significantly lower than those without thymoma at 1 and 3 years(P=0. 049, P=0. 000, P=0. 015, P=0. 010), but no differences at 5 years (P= 0. 457, P= 0. 699). The survival rates were lower in MG with thymoma than without thymoma (Log rank = 18.58,P = 0. 000). Conclusion: The clinical characteristics are different between MG with and without thymoma. The remission of symptom of MG- with thymoma is worse than that of MG without thymoma in the near future, but similar in the long future. In a long-term, the death rate of MG with thymoma is significantly higher than that of MG without thymoma.