Background: NOTCH1 pathway activation has been recently described to be a key player in gastric carcinogenesis, enhance the survival and proliferation of cancer stem cells (CSCs) and mediate chemoresistance in several malignancies. Aim: This study investigated the correlation between NOTCH1 and CSC marker OCT4 (octamer binding transcription factor‑4) expression and the clinicopathological properties, survival and treatment outcome in patients with gastric carcinoma (GC) receiving adjuvant chemotherapy. Materials and Methods: NOTCH1 and OCT4 were immunohistochemically detected in 50 post‑operated specimens of GC. Patients’ data regarding disease‑free survival (DFS), overall survival (OS), and the response to the chemotherapy was statistically analyzed. Results: NOTCH1 and OCT4overexpression was detected in 60% and 52% of GC tissues, respectively, and that was significantly higher than the rates in adjacent non‑neoplastic gastric mucosa (P < 0.05). A significant correlation was detected between overexpression of NOTCH1 and OCT4 in GC and aggressive clinicopathological features; poor differentiation (P = 0.021, P = 0.037, respectively), depth of tumor invasion (P < 0.001 for both), TNM stage (P < 0.001 for both), lymph node metastasis (P = 0.002, P = 0.003, respectively) and distant metastasis (P < 0.001 for both). NOTCH1 was positively correlated with OCT4 (P = 0.002). Survival analysis disclosed that upregulation of NOTCH1 and OCT4 was associated with worse DFS (P = 0.013, P < 0.001, respectively) and OS (P < 0.001 for both). Overexpression of NOTCH1 and OCT4 correlated with poor response to chemotherapy (P = 0.013, P = 0.005, respectively) and worse clinical outcome. Conclusion: Combined detection of these proteins might disclose even better predictive value for shorter survival and resistance to chemotherapy