Sixty-five patients with unresectable advanced epithelial ovarian cancer who underwent exploratory laparotomy or unilateral oophorectomy were reviewed. Forty-five of 65 patients received 3.8 cycles of neoadjuvant chemotherapy (NAC) and were successfully debulked at interval cytoreductive surgery (IRS); 31 of 45 showed no evidence of disease. Patients with residuals <1 cm at IRS had a high possibility of achieving clinical remission. Patients who failed to receive IRS showed poor prognosis. Also, 63 patients who underwent conventional primary debulking surgery with residuals >1 cm were investigated as a contrast. No significant difference was observed in patient survival between the NAC group and the conventional treatment group. NAC and IRS offered patients with unresectable tumors survival similar to that of those with suboptimally resectable tumors at primary debulking. We conclude that this strategy has potential benefits for the patients with clinically aggressive ovarian cancer who are unable to receive standard treatment.