We evaluated the prognostic significance of postoperative re-elevation of cancer antigen-125 (CA-125) levels in patients with ovarian cancer and preoperative normalization of CA-125 levels after neoadjuvant chemotherapy (NAC).The data of 103 patients with preoperative CA-125 normalization after NAC at the Yonsei Cancer Hospital (2006-2017) were analyzed. We compared the clinical characteristics and survival outcomes among patients with normal postoperative CA-125 levels and those with re-elevated CA-125 levels after interval debulking surgery (IDS). CA-125 elevation was defined as levels >35 U/mL.Among 103 patients, 52 (50.5%) and 51 (49.5%) had normal and re-elevated CA-125 levels after IDS, respectively. Patients with CA-125 re-elevation underwent more radical surgeries during IDS than those with normal CA-125 levels (p = 0.018). We found no significant differences in progression-free survival (PFS; p = 0.726) or overall survival (OS; p = 0.293) between the two groups. Moreover, patients with persistent CA-125 elevation (3 weeks after IDS) did not have inferior PFS (p = 0.171 and p = 0.208, respectively) or OS (p = 0.128 and p = 0.095, respectively) compared to patients with early normalization (within 3 weeks of IDS) or normal CA-125 levels. Multivariate regression showed that CA-125 re-elevation had no effect on recurrence (hazard ratio [HR], 0.75; 95% confidence interval [CI], 0.43-1.30) or death (HR, 0.99; 95% CI, 0.33-2.98).Among patients with preoperative CA-125 normalization after NAC, postoperative CA-125 re-elevation had no prognostic value. Novel and reliable biomarkers reflecting the tumor response after IDS should be identified.