Background: Understanding the incidence and timing of venous thromboembolic (VTE) events among patients receiving treatment for advanced endometrial cancer (EC) may help to inform VTE risk stratification and consideration of thromboprophylaxis. We aimed to describe the rate of VTE at each stage of primary treatment for advanced EC as well as the baseline Khorana Score (KS) distribution in this population. Methods: This was a retrospective cohort study of patients diagnosed with stage IVB EC from January 2001 to July 2020 at a single academic institution. The primary outcome was VTE incidence at each stage of primary treatment (at diagnosis, during neoadjuvant chemotherapy [NACT] if applicable, post-operatively [< 30 days from surgery], or during adjuvant chemotherapy). Subjects who were anticoagulated at EC diagnosis were excluded. Khorana score was calculated according to established parameters (1 point each for gynecologic malignancy, pre-chemotherapy platelet count ≥ 350, hemoglobin < 10 or use of red blood cell growth factors, leukocyte count >11, and BMI ≥ 35). Descriptive statistics were used for analysis. Results: There were 76 patients diagnosed with stage IVB EC, 2 of whom were excluded for anticoagulation at cancer diagnosis. Of the remaining 74 patients, 58 underwent primary surgery (78%) and 16 received NACT (22%). A total of 59 received adjuvant chemotherapy after either primary or interval debulking surgery. The two predominant tumor histologies were serous (48%) and endometrioid (20%).A total of 16 VTE occurred during the primary treatment course (22%), 11 among the cohort receiving primary surgery (19%) and 5 among the cohort receiving NACT (31%). The distribution of VTE by stage of primary treatment is shown in Table. The rate of VTE was highest during adjuvant chemotherapy. There were 62 patients for whom a Khorana score could be calculated either before NACT or adjuvant chemotherapy. The distribution of KS was: 17 (27%) with KS 1 (low risk) and 45 (73%) with KS ≥ 2 (intermediate – high risk). Of the 11 non-postoperative VTE, 3 patients (27%) had KS 1 and 8 (73%) had KS ≥ 2. Conclusions: The incidence of VTE among patients with advanced EC was high regardless of whether treatment was initiated with NACT or primary surgery. The majority of VTE occurred among patients with a high KS, but those with a low KS remained at risk. Thromboprophylaxis among all patients with advanced EC may be warranted, and larger studies are needed to determine the performance of KS as a VTE predictor in advanced EC.