Objective To study the expression and its clinical significance of p16 in human gastric carcinomas. MethodsThe expression of p16 protein and mRNA in human gastric carcinomas using SP immunohistochemical and in situ hybridization (ISH) methods were examined. Results Of the 85 cases tested, 65.88% (56 cases) showed positive staining of p16 protein in the primary lesions. The positive rate of p16 protein was significantly lower in the cases with deep invasion, poor differentiation or shorter survival periods (Ｐ＜0.05). The positive rate of p16 mRNA expression in human gastric carcinomas was 47.37% (in 38 cases). Conclusion p16 gene may correlate with the development and progress of gastric carcinomas. The expression of p16 gene may be a useful tool for showing biological behavior and prognosis of human gastric carcinomas.