Abstract Background: It is well known that Lynch syndrome increases risk of endometrial and colorectal cancer. There is not much study about detecting Lynch syndrome patient fast among Korean population by gynecologic oncology surgeon. We undertook this study to investigate this. Methods: A review of endometrial cancer patients who was counseled about Lynch syndrome in Department of Obstetrics and gynecology, Samsung Changwon Hospital by single surgeon was done. Clinical information was extracted from the medical record including age, family and personal history of cancer, immunohistochemistry(IHC), microsatellite instability test(MSI), and gene sequencing results. Risk management and posttest education after result were offered about risk reducing options and cascade testing for affected individual Results: App patient was 16.There were two germline mutations (both MSH2) (c.23C>T (p.Thr8Met), c.187delG (p.Val63*).Both were negative for MSH2 IHC, But no patient matched criteria of Amsterdam. Four variation of unknown significance (VUS) was found (Three MSH2 and One MLH1).Among those all were abnormal in IHC and there was only one Amsterdam criteria matched patient. There were two unstable MSI patients, one was MSH2 germline mutation and the other was MSH2 VUS. Median age was 57(41~76).Most cases were endometrioid type (11/16, 69 %).Seventy five percent were stage I(12/16). Conclusion: Two MSH2 germline mutation patients among this population was found. Gynecologic oncology surgeon can be adapted to develop the ability to assess and evaluate genetic risk among endometrial cancer. Citation Format: Min Kyu Kim, Min Jung Kwon, Min Jeong Yun. Gate keeping role for endometrial cancer about Lynch syndrome by surgeon [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 4284. doi:10.1158/1538-7445.AM2017-4284