Abstract: Objective 　To study the expression of Smac and Ki67 in gastric cancer and the correlation of Smac and Ki67, the clinical significance as well. Methods 　Immunohistochemical staining of Smac and Ki67 expression was performed by the standard streptavidin-peroxidase ( SP) technique for the paraffin sections of 71 gastric cancers. The relationship between the Smac expression and the clincopathological parameters, prognosis or the cell proliferation index Ki67 was analyzed. Results 　The positive rate of Smac in gastric cancer was 71. 8 %(51/ 71), all of the normal gastric tissues expressed Smac (20/ 20) . The positive rate of Ki67 expression in gast ric cancer was 66. 2 %(47/ 71) . Significant correlation was found between Smac and Ki67 expression with histological differentiation grade, tumor depth, lymph node metastasis, TNM stage of gastric cancer ( P < 0. 05) . The Ki67 expression in negative expression of Smac (17/20) was significantly higher than that in positive expression of Smac (30/ 51, P < 0. 05) . The survival time of patients with Smac-positive tumors was significantly longer than that of Smac-negative tumors ( P <0. 05) . Conclusion 　The Smac and Ki67 expression can serve as an important parameter of malignant degree and prognosis of gastric cancer. Smac expression was significantly correlated with Ki67 expression.