Abstract Background: PARP-1 overexpression has been identified in several malignancies. Few studies have handled the expres-sion of PARP-1 protein in gastric carcinoma and its associations with outcome. Aim of Study: This study aimed at exploring the signifi-cance of PARP-1 expression in gastric adenocarcinoma and correlation with HER2 status. Subjects and Methods: Quantitative expression of PARP-1 proteins was assayed by Immunohistochemistry in 40 cases of gastric adenocarcinoma. PARP-1 mRNA was moreover evaluated by Quantitative Real-Time Polymerase Chain Re-action. Results: The level of expression of mRNA expression level was significantly increased in 25 of 40 (62.5%) of gastric adenocarcinoma tissues compared with the corresponding adjacent non cancer tissues (p < 0.001). Positive expression of PARP-1 protein was detected in 23/40 (57.5%) of gastric adenocarcinoma. PARP-1 expression in cancer tissues was significantly higher than adjacent non-cancerous tissue (p < 0.001). The aberrant high expression of PARP-1 showed significant correlation with depth of invasion (p < 0.001), advanced stage (p < 0.001), nodal (p < 0.05) and distant metas-tasis (p < 0.001). Positive correlation was detected between PARP-1 and positive HER2 status (p < 0.001). Conclusion: PARP-1 level is up regulated significantly in gastric adenocarcinoma tissue. PARP-1 is positively corre-lated with positive HER2 status and poor prognostic factors. PARP-1 might be potential prognostic marker for gastric adenocarcinoma.