Objective: To determine prognostic factors for women with ovarian carcinosarcoma (OCS). Material and Methods: A multicenter, retrospective department database review was performed to identify patients with OCS at eight gynecologic oncology centers in Turkey. Demographic, clinicopathological, and survival data were collected. Results: We identified 94 patients with OCS. The median age was 60.0 years (range, 31-78), and the median follow-up duration was 36.0 months (range, 4-188). After primary cytoreductive surgery, 61 (64.9%) patients had ≤1 cm of residual disease (optimal debulking), whereas 33 (35.1%) had >1 cm of residual disease (suboptimal debulking). For the entire cohort, the 5-year progression free survival (PFS) rate was 25.2%, whereas the 5-year overall survival (OS) rate was 49.4%. Women with optimal cytoreduction had a median PFS of 41.0 months (95% Confidence Interval [CI]: 19.71-62.28, Standard Error [SE]: 10.86) compared with women with suboptimal cytoreduction who had a median PFS of 15.0 months (95% CI: 8.79-21.21, SE: 3.16; p=0.011). The 5 year OS rate for women with optimal cytoreduction was significantly higher than that of women with suboptimal debulking (57.6% vs. 33.9%; p=0.005). Positive peritoneal cytology (hazard ratio [H]: 2.35, 95% CI: 1.19-4.63; p=0.013) and suboptimal cytoreduction (H: 2.61, 95% CI: 1.32-4.99; p=0.004) were independent risk factors for decreased OS. Conclusion: Suboptimal cytoreduction seems to be an independent prognostic factor for decreased OS in women with OCS.