The purpose of this study was to evaluate the pattern and quality of care for ovarian cancer in Germany and analyze prognostic factors with emphasis on characteristics of treating institutions, hospital volume, and participation in clinical trials. This study utilized national survey including patients with histologically proven invasive epithelial ovarian cancer diagnosed in the third quarter of 2001 including descriptive analysis of pattern of surgical care and systemic treatment in early (FIGO I-IIA) and advanced (FIGO IIB-IV) ovarian cancer and both univariate and multivariate analysis of prognostic factors. One third of all patients diagnosed in the third quarter of 2001 in Germany, 476 patients, were included. Standard care according to German guidelines was provided to only 35.5% of patients with early ovarian cancer. Recommended chemotherapy was given to 78% in advanced disease. Multivariate analysis showed advanced stage, poor performance status, comorbidity, ascites, and treatment in an institution not participating in cooperative studies to be associated with inferior survival. Non-participation was associated with an 82% increase of risk (HR = 1.82; 95% CI, 1.27-2.61; P= 0.001). Hospital volume did not affect treatment outcome. Adherence to treatment guidelines showed remarkable variety among German hospitals, indicating options and need for improvement. Selecting an institution that participates in cooperative trials might be an option for individual patients seizing the chance for better quality of care even when individual factors might hamper enrollment in a study.