Despite its fall in incidence, gastric adenocarcinoma remains a common disease with dismal prognosis worldwide. A better understanding of its tumorigenesis and biologic properties of tumor cells related to invasion and metastasis is crucial to improving diagnosis and treatment. Conflicting results concerning the relationships between overexpression of PAI-1, c-erbB2, and p53 protein and biologic behavior of gastric carcinoma have been noted. The aim of this study was to evaluate the value of overexpression of PAI-1, c-erbB2, and p53 protein as prognostic factors in gastric adenocarcinoma. Overexpression of PAI-1, c-erbB2, and p53 protein by immunohistochemistry was correlated with variable clinicopathological parameters and patients' survival in 80 cases of gastric adenocarcinoma. Overall PAI-1 expression rate was 63.7% (51/80) and higher in advanced cancer (p=0.0003) and nodal metastasis (p=0.003) groups. Overall c-erbB2 expression rate was 43.8% (35/80) and higher in antral (p=0.03), differentiated (p=0.001), intestinal (p=0.0007), and expanding (0.03) groups. The p53 protein overexpression was 37.5% (30/80) and higher in early cancer (p=0.02), differentiated (p=0.006) and intestinal groups (p=0.009). Patients with PAI-1, c-erbB2, and p53 protein positive tumors tended to have poorer survival rates than patients with PAI-1, c-erbB2, and p53 protein negative tumors, but the difference was not statistically significant (p=0.25, 0.37, 0.52). Our data indicated that PAI-1 overexpression is one of the poor prognostic factors in gastric adenocarcinoma and c-erbB2 and p53 protein seem to be involved in the early stage of carcinogenesis of intestinal type-gastric adenocarcinoma.