Retrospective analyses suggest that a subgroup of patients with Stage III and IV ovarian carcinoma can be treated with neo-adjuvant chemotherapy followed by interval debulking surgery. The absolute indications for neo-adjuvant chemotherapy appear to be Stage IV disease (excluding pleural fluid) or metastases of more than 1 g at sites where resection is impossible. In patients with an estimated total metastatic tumor load of >100 g, the presence of at least two of the following relative indications for neo-adjuvant chemotherapy are considered to be necessary: 1) uncountable (>100) peritoneal metastases, 2) estimated metastatic tumor load of >1000 g, 3) presence of large (>10 g) peritoneal metastatic plaques, 4) large volume ascites, and 5) World Health Organization (WHO) status II or III. Interval debulking surgery in patients with suboptimal primary debulking surgery has been proven effective in increasing overall survival and progression-free survival in a large prospective, randomized trial of the European Organization for Research and Treatment of Cancer (EORTC). The strategy of neo-adjuvant chemotherapy, followed by interval debulking surgery, should be confirmed in a prospective randomized trial. The EORTC 55971 trial is currently addressing this issue. We will review the studies on primary chemotherapy, interval debulking surgery, and the indications for primary chemotherapy followed by interval debulking surgery, and ongoing trials.