Objective To determine the expression of sodium-hydrogen exchanger (NHE) 1 in gastric carcinoma tissue,and investigate the relationship between NHE1 expression and clinicopathological characteristics.Methods The expression levels of NHE1 mRNA and protein were detected in both gastric carcinoma tissue (48 cases) and paraneoplastic tissue (40 cases) by reverse transcription polymerase chain reaction (RT-PCR) and Western blot.The relationship between the expression levels of NHE1 mRNA and protein and the clinicopathological characteristics was analyzed.Results The relative expression levels of NHE1 mRNA and protein in gastric carcinoma tissue were 0.791 ± 0.286 and 1.475 ± 0.142,in paraneoplastic tissue were 0.352 ± 0.069 and 0.329 ± 0.048,and there were statistical differences (P ＜ 0.01).The expression level of NHE1 mRNA was positively correlated with NHE 1 protein in the gastric carcinoma tissue (r =0.375,P ＜ 0.05).The expression levels of NHE1 mRNA and protein were associated with the depth of invasion,lymph node metastasis and TNM staging (P ＜ 0.05).However,the expression levels of NHE1 mRNA and protein were no associated with age,gender and tumor differentiation (P ＞ 0.05).Conclusion The expression levels of NHE1 mRNA and protein are significantly up-regulated in gastric carcinoma tissue,which may be involved in the development of gastric carcinoma.