Introduction and hypothesis: We aimed to investigate whether the Manchester procedure affects the risk and prognosis of endometrial cancer. Methods: All Danish residents have a personal number permitting linkage of nationwide registers on the individual level enabling epidemiological studies with lifelong follow-up. We performed a nationwide historical cohort study including Danish women born before 2000 undergoing the Manchester procedure (N = 23,935) during 1977–2018. We included women undergoing anterior colporrhaphy as a reference group (N = 51,008) because of comparable inclination to consult a doctor and clinical similarities. Main outcomes were the number of women diagnosed with endometrial cancer, the stage of endometrial cancer at time of diagnosis, and cancer-specific and overall mortality. We followed the cohort until endometrial cancer/death/emigration/hysterectomy/31 December 2018. We performed chi-square test for trend to compare the diagnostic stage and Cox regressions to analyze the risk of endometrial cancer and mortality. The models were adjusted for age, calendar year, income level, and parity. Results: During follow-up (median 13 years), 271 (1.13%) women were diagnosed with endometrial cancer after the Manchester procedure and 520 (1.05%) after anterior colporrhaphy. The adjusted hazard ratio (HR) for endometrial cancer was 1.00 [95% confidence interval (CI) 0.86–1.16]. No difference in stage of cancer was found (p = 0.18) nor when stratifying for calendar year. The HR for cancer-specific mortality and overall mortality after the Manchester procedure was 0.87 (95% CI 0.65–1.16) and 0.93 (95% CI 0.77–1.12), respectively. Conclusions: The Manchester procedure does not affect the risk or prognosis of endometrial cancer.