Background: Sentinel Lymph Node Biopsy is a technique developed to predict lymphatic involvement in patients with early endometrial cancer, decreasing the morbimortality associated with routine systematic lymphadenectomy and improving quality of life. Main Objective: To determine the detection rate and negative predictive value of the Sentinel Lymph Node Biopsy by Immunofluorescence in patients with early endometrial cancer. Methods: A descriptive observational study in patients with early endometrial cancer (FIGO stage I-II) for all histological types and grades, who underwent the Sentinel Lymph Node by immunofluorescence Technique, between June 2019 and March 2020 at the Fundación Jiménez Díaz University Hospital. We used indocyanine green powder for injection, with a concentration of 25 milligrams (mg). We proceeded to dissolve it in 10 cubic centimeters (cc) of distilled water to. After which, we injected 2 cc of the prepared solution into the cervix at the 3 and 9 o’clock positions at a depth of 1 centimeter. Results: Eighteen patients were included, analysing a total of 26 sentinel nodes: 24 pelvic and 2 paraortic; and a total of 273 lymph nodes (sentinel and non-sentinel nodes): 83 right pelvic, 86 left pelvic and 104 paraortic. All nodes were negative for metastasis. Global and bilateral detection rates were 77.78% and 50% respectively. The Negative Predictive Value and sensitivity were 100%. No significant difference in morbimortality was found between performing only Sentinel Lymph Node technique or systematic lymphadenectomy, but the association with quality of life was significant, with better results for those who only underwent the sentinel lymph node technique versus systematic lymphadenectomy (0% vs 77%). Conclusion: The global and bilateral detection rates of the Sentinel Lymph Node Technique by immunofluorescence were 77.78% and 50% respectively, obtaining a Negative Predictive Value and Sensitivity of 100%. Sentinel Node Biopsy is a valid technique to predict lymphatic affectation in early endometrial cancer, with lower morbimortality than systematic lymphadenectomy.