The role of cytoreductive surgery (CS) in recurrent ovarian cancer (ROC) has not been clearly defined. We performed a retrospective study evaluating criteria for CS in ROC. Twenty-five institutions documented their patients with CS for invasive epithelial ROC performed 2000-2003. Two hundred sixty-seven patients were included. Complete tumor removal was achieved in 133 patients (50%). Complete resection was associated with prolonged survival compared to surgeries with residual tumor. Median survival of patients without residual tumor was 45.3 months and of patients with residual tumor, irrespective of its size, 19.0 months (HR 4.33; 95% CI 2.53-7.43; P < 0.0001). In a multivariate analysis, the following factors showed a significant influence on the probability to achieve a postoperative residual tumor of 0 mm: absence of ascites (<500 vs > or =500 mL: HR 4.63; 95% CI: 1.81-11.76; P= 0.0001), good performance status Eastern Cooperative Oncology Group (ECOG) 0 vs >0: HR: 2.41; 95% CI: 1.41-4.08; P= 0.001, and low FIGO stage at primary diagnosis (FIGO I/II vs III/IV: HR 1.87; 95% CI: 1.04-3.37; P= 0.036). Significant factors for survival after surgery for recurrence in a multivariate analysis were achievement of complete resection (residual tumor at surgery for recurrence 0 vs >0 mm: HR 2.86; 95% CI: 1.66-4.93; P < 0.001), absence of ascites (<500 vs > or =500 mL: HR 2.09; 95% CI: 1.18-3.71; P= 0.012), and application of a platinum-containing chemotherapy (platinum-containing chemotherapy vs others: HR 1.83; 95% CI: 1.16-2.88; P= 0.009). Only patients with complete resection seem to benefit from CS. This new panel of selection criteria will be evaluated in a prospective study.