Objectives: Serous ovarian carcinoma (SOC) is a biologically heterogeneous with different genomic and molecular profiles, beside clinical response to the chemotherapy with subsequent in obstacles in starting unified, acceptable treatments and so we assess immunoexpression of Nanog, ZEB1, and EpCAM in SOC. Methods: In this study, the immunoexpression of Nanog, ZEB1, and EpCAM was studied in 60 cases of SOC. Overall survival (OS), disease-free survival (DFS) data and response to chemotherapy were analyzed. Results: NANOG was immunostained in 65% of the cases with a significant association with tumor grade, lymph node metastasis, and FIGO stage (p < 0.001 for each). ZEB1 showed moderate- high expression in 58.3% of the cases with significant up-regulation of ZEB1 expression with SOC grade, nodal metastasis, and SOC FIGO stage (p<0.001). EpCAM revealed high expression in 60% of the cases with significant association with higher grade, nodal metastasis, and advanced stage (p < 0.001 for each). Up-regulation of Nanog was significantly associated with response to chemotherapy, relapse, shorter OS and DFS (p < 0.001 for each). ZEB1 overexpression exhibited a significant association with response to chemotherapy (p= 0.012), relapse, shorter OS and DFS (p<0.001 for each). Moreover, the high EpCAM had a significant association with response to chemotherapy (p= 0.043), relapse (p < 0.001) shorter OS (p=0.006) and DFS (p< 0.001). Conclusions: Up-regulation of Nanog and ZEB-1 and EpCAM perhaps promote an aggressive SOC with a high risk of relapse and unfavorable response to standard chemotherapy regimen.