Abstract: Objective: To investigate the expression of amplified in breast cancer 1(AIB1) in gastric carcinoma and its clinical significance.Methods: The expressions of AIB1 in gastric carcinoma tissue(n=88) and Para-cancerous tissue(n=85) were detected by immunohistochemical method.The relationship between AIB1 expression and clinicopathologic features was analyzed.Results: The positive rates of AIB1 expression in 88 gastric carcinoma samples and 85 Para-cancerous samples were 75.0% and 7.1%,respectively,the difference of which was statistically significant(P<0.01).The differences of positive AIB1 expression in lymph node metastasis and clinical stages were statistically significant(P<0.01),but the differences of AIB1 expression in sex,age,size of tumor,degree of differentiation and depth of tumor infiltration were not statistically significant(P>0.05).Conclusions: The high expression of AIB1 protein in gastric carcinoma tissue may be associated with the occurrence,development and metastasis of gastric cancer.