Abstract: Objective To investigate the methylation status of promoter of HOXA10 gene in lung adenocarcinoma and its correlation with clinicopathologic characteristics and prognosis. Methods Methylation-specific polymerase chain reaction（MSP）was used to examine the promoter hypomethylation in 30 lung adenocarcinoma samples and their corresponding lung normal tissues. The relationship between the hypomethylation status and clinicopathologic features， prognosis was analyzed. Results MSP test indicated that 17 cases（56.7％）of 30 lung adenocarcinoma samples showed hypomethylation of HOXA10 promoter，and 4 cases were even complete demethylation. But only 6 cases（20.0％）of 30 corresponding lung normal tissues showed promoter hypomethylation（P＜0.05）. Analysis revealed that the frequency of hypomethylation was correlated with size of tumor，clinical stage and lymph node metastasis（P＜0. 05），but not with age，gender and tumor differentiation（P＞0.05）. Statistical analysis showed that the median diseasefree survival of patients with HOXA10 hypomethylation was 27.0 months，which was significantly lower than 46.0 months of those with HOXA10 methylation（P=0.002）. Conclusion HOXA10 gene promoter hypomethylation is a frequent epigenetic event in lung adenocarcinoma，which indicates poor prognosis of patients. It may be a biological marker to predict the prognosis for lung adenocarcinoma.