An estimated 3% of endometrial cancers are caused by Lynch Syndrome. These can be identified via a step-wise testing pathway of somatic tumour testing followed by germline gene testing. Using complete national data amalgamated from diagnostic laboratories via the English National Disease Registration Service, we conducted a retrospective national population-based observational study of Lynch Syndrome testing in all endometrial cancers diagnosed in 2019-2020. We explored the proportions tested, median time to test, and yield of abnormal results, as well as the factors influencing these values. We found important regional variations in testing proportions, delays, and missed opportunities to diagnose Lynch Syndrome.  These data form a baseline ahead of the NICE guidance on universal Lynch Syndrome testing in endometrial cancer issued in 2020. (By Dr. Catherine Huntley, https://jmg.bmj.com/content/early/2024/10/21/jmg-2024-110231 )