Background: Outcome of patients with ovarian cancer depends largely on treatment quality and expertise of treating physicians and centers. To assess treatment reality and quality in Germany, we initiated a nationwide quality assurance program. Methods: All German hospitals treating patients with ovarian cancer were asked to document their patients with primary diagnosis of epithelial ovarian cancer in the third quarters of 2012 and 2016. Details of tumor, treatment and outcome were documented in a central database. The current analysis focuses on patients with high-grade AOC stage III/IV. Results: In total, 1010 patients with high-grade AOC were documented. This represents 63% of all patients diagnosed with AOC in Germany in these periods. Median age was 65 years. The majority (774/1010 - 76.6%) were diagnosed with stage III disease and 947/1010 (93.8%) had serous, 34 (3.4%) endometrioid and 29 (2.9%) clear cell histology. 915/1010 (90.6%) had primary cytoreductive surgery. Complete resection was achieved in 434/915 (47.4%) at primary surgery and in 54/95 (56.8%) at interval debulking surgery. Median PFS and OS in patients with primary surgery and complete resection was 29.7 months and 63.1 months compared to 16.8 months and 30.7 months in patients with residual disease (HR PFS 0.46 95% CI 0.22-0.54 HR OS: 0.38 95% CI 0.31-0.45). In patients with neoadjuvant chemotherapy and interval debulking, median PFS and OS were 24.3 and 50.7 months with complete resection, compared to 15.4 and 33.9 months with residual disease (HR PFS 0.61 95% CI 0.38-0.95 HR OS: 0.48 95% CI 0.28-0.83). First-line chemotherapy was carboplatin/paclitaxel (TC) in 919/1010 (91%) of the patients, 627 (62%) also received bevacizumab (TCB) and 544 of these (87%) also received maintenance therapy. Median PFS and OS in patients with TCB was 23.3 months and 46.2 months and 18.5 months and 39.0 months in patients treated with TC (p = 0.049: HR 0.85, 95% CI 0.72-1.00 and p = 0.012: HR 0.79, 95% CI 0.65-0.95). The rate of complete tumor resection at surgery as well as the use of bevacizumab increased between the two periods. Conclusions: Based on this representative cohort of patients with advanced ovarian cancer in Germany, the majority of patients is treated with primary surgery followed by carboplatin/paclitaxel and bevacizumab. Patient outcome regarding PFS and OS was best when complete tumor resection was achieved at primary surgery and patients received combination chemotherapy with maintenance treatment. Supported by Roche, Amgen, AstraZeneca, Boehringer Ingelheim, GlaxoSmithKline, Essex.