Introduction Endometrial cancer is the most common malignant tumor of the female genital organs. In Germany, treatment is provided in both cancer centers certified by the German Cancer Society (Deutsche Krebsgesellschaft, DKG) and in non-certified hospitals. This study investigated whether treatment in DKG-certified centers leads to improved overall survival of patients with endometrial cancer. Materials and Methods Data from 11 legally independent German statutory health insurance (SHI) funds of the AOK were analyzed as well as data from four clinical cancer registries (CCR), resulting in inclusion of 30 102 AOK patients and 8190 registry patients with a diagnosis (incidental cases) of ICD-10-GM code C54 (malignant neoplasm of corpus uteri). For comparative survival analyses, multivariable Cox regressions and Kaplan-Meier analyses were used. Results The Kaplan-Meier estimator for 5-year overall survival was 66.7% for patients from certified centers and 65.0% for patients from non-certified hospitals (using SHI data; CCR data: 63.4% vs. 60.7%). Cox regression adjusted for relevant confounders showed a hazard ratio (HR) of 0.93 (SHI data; 95% CI 0.86 - 1.00; p = 0.050) and 0.935 (CCR data; 95% CI 0.827 - 1.057; p = 0.281) for all-cause mortality. In a subgroup analysis (CCR), patients with International Union against Cancer Control (UICC) stage I had a significant survival benefit if treated in a certified center (HR 0.783; 95% CI 0.620 - 0.987; p = 0.038). Conclusion The study presented herein shows that patients with endometrial cancer treated in a certified cancer center tend to have better survival rates. This should be considered when selecting the treating hospital.