urpose: This study evaluated the appropriate number of cycles of neoadjuvant chemotherapy (NAC) before interval debulking surgery (IDS) in advanced ovarian cancer. Materials and Methods: Cases with advanced ovarian cancer who received a combination of taxane and platinum as NAC and IDS at this institution between 2001 to 2016 were identified. The cases were divided into two groups; patients who received six or four scheduled cycles of NAC (groups A and B, respectively). Results: Thirty-six cases were in group A and 35 cases in group B. Progression-free survival (PFS) and overall survival (OS) in group A were better than those in group B (p = 0.01, < 0.01). In multivariate analysis, six scheduled cycles of NAC was an independent better prognostic factor for PFS (hazard ratio (HR), 0.56, p = 0.04) and OS (HR, 0.39; p = 0.01). Conclusion: In advanced ovarian cancer, six scheduled cycles of NAC demonstrated a better prognosis.