e16123 Background: Venous thromboembolism (VTE) commonly manifests as a postoperative complication of gastroesophageal cancer (GEC) surgery. However, guidelines seldom differentiate preventive approaches for postoperative VTE based on cancer types. Furthermore, there is a lack of research evaluating factors associated with the risk of thrombosis for patients diagnosed with GEC who undergo surgery. Herein, we aim to determine the incidence of VTE after GEC surgery and the clinical characteristics of the patients associated with VTE events. Methods: We retrospectively reviewed the charts of patients diagnosed with GEC and underwent gastrectomy/esophagectomy at Cleveland Clinic, OH, and Weston, FL, between 2005 and 2022. Patients who had non-malignant diseases or did not undergo invasive surgery were excluded. Of the 437 patients who underwent GEC surgery, only 375 met the inclusion criteria. Patients who developed a VTE event diagnosed by imaging studies within one year of GEC surgery were considered positive for the event. DVT prophylaxis (DDPX) was defined as the administration of anticoagulants, such as heparin and enoxaparin. The average length of DVT prophylaxis was 7 days. The chi-square test was used to assess the significant differences among the groups based on VTE status. Results: In this cohort of 375 patients, 54 (14.4%) patients experienced VTE. 43 patients (79.60%) who experienced a VTE event received DDPX, whereas 10 patients (18.50%) with VTE did not receive DDPX. Of the 321 patients who did not develop VTE, 251 patients (78.20%) received DDPX, while 66 patients (20.60%) did not receive DDPX. DDPX administration in both cohorts was not significantly different (p 0.868). Notably, 36 (66.7%) of the patients developed VTE events within 30 days following GEC surgery, with a subsequent significant decrease in VTE incidence beyond this timeframe (9.3%, 7.4%, 11.1%, and 5.5% in the 30-60-, 60-90, 90–180, and 180-365-day intervals, respectively, p < 0.001). Among the patients who presented with gastrointestinal stromal and neuroendocrine tumors (7.50%), none of the patients developed a VTE event. Nevertheless, 19.35% of the 31 patients diagnosed with squamous cell carcinoma had a VTE within one year of GEC. Patients with Stage IV disease had a higher risk of VTE compared to lower-stage disease (25.95%, p 0.032). However, factors such as BMI, smoking status, type of surgery, treatment regimens, and ECOG score were not significantly associated with VTE. Conclusions: Patients diagnosed with GEC who underwent surgical intervention demonstrated a significant propensity for VTE, particularly within 30 days post-surgery. The rate of VTE incidence was not significantly different among the DPPX and non-DPPX cohorts, which could be attributed to the short duration of anticoagulation. Further studies are warranted to investigate the optimal duration of DDPX.