Background: The prognostic significance of serum lactate dehydrogenase (LDH) level in thymic carcinoma (TC) remains unclear. Therefore, we evaluated the role of pretreatment serum LDH level in the prognosis for TC in this study. Methods: Sixty consecutive surgical patients were analyzed in this study with pathologic confirmed TC in Sun Yat-sen University Cancer Center from June 1996 to June 2014. Results: The cut-off value of LDH was 210.50 IU/L. In both univariate analysis and multivariable analysis, only pretreatment serum LDH level (P= 0.027) and pathological Masaoka stage (P= 0.041) were associated with overall survival (OS). In univariate analysis, pretreatment serum LDH level, tumor size, postoperative radiotherapy (PORT) and pathological Masaoka stage were associated with disease-free survival (DFS) (all P< 0.050). Multivariable analysis showed that LDH level (P= 0.001), PORT (P= 0.001) and pathological Masaoka stage (P= 0.038) were independently prognostic factors of DFS. This study also revealed that male patients and larger tumor size had a significantly higher rate of elevated pretreatment serum LDH level than in the other groups. Conclusions: In conclusion, pretreatment serum LDH level was an independent prognosis factor of OS and DFS for patients with TC.