Abstract: Objective To investigate the expression and significance of NF-kB p50 and NF-kB p65 protein in gastric carcinoma and normal tissues adjacent to carcinoma and to evaluate the relationship between the expressions and the clinical pathologic factors. Methods High throughput technology of tissue microarray and immunohistochemical SP method were applied to detect the expressions of NF-kB p50 and NF-kB p65 protein in129 gastric carcinoma specimens that did not have a history of chemo-radiotherapy and 101 non-tumor gastric tissues. The followed-up cases were used for prognosis analysis. Results In gastric carcinoma tissue and normal gastric tissue, the rates of the expression of NF-kB p50 protein were 84.5%and 32.7% respectively(P<0.05).High NF-kB p50 expression related to tumor TNM stage, differentiation and lymph node metastasis ( P <0.05). The rates of the expressions of NF- kB p65 protein were 79.1% in gastric carcinoma tissue while 27.7% in normal tissues adjacent to carcinoma. NF-kB p65 protein showed relationship with tumor TNM stage and lymph node metastasis (P<0.05). Patients with negative expression for NF-kB p50 and NF-kB p65 had much higher survival rates than those with positive expression (all P<0.01). Cox proportional hazard regression model analysis showed that NF-kB p50 and TNM stage were associated with the prognosis of gastric carcinoma patients, and could be used as an independent prognostic factor. Conclusions In the evolution of gastric carcinoma, the over expression of NF-kB p50 and NF-kB p65 expression may cause abnormal cell proliferation and differentiation, leading to the occurrence and development of tumor