OBJECTIVE: To determine the incidence of clinical and subclinical venous thromboembolic events (VTE) in patients with locally advanced cervical cancer (LACC) treated with high-dose thromboprophylaxis during definitive chemoradiation and brachytherapy. METHODS: A prospective observational study was undertaken from August 2021 to December 2023 in patients with primary LACC treated with definitive chemoradiation in two Dutch tertiary hospitals. Patients received high-dose thromboprophylaxis during chemoradiation and brachytherapy. In week 4 or 5 of the overall treatment time, plasma D-dimer levels were determined, and all patients underwent venous ultrasound imaging of the legs to screen for deep vein thrombosis (DVT). If indicated, patients received a CT-angiography to screen for pulmonary embolism (PE). RESULTS: Among 89 included patients, cumulative incidence of clinical and subclinical (V)TE was 7.9 % (n = 7). DVT was found in two patients, PE in three patients, DVT and PE in one patient and one patient had an arterial thromboembolic event (ATE). Of these patients, three (3.4 %) had subclinical VTE, diagnosed during the screening before brachytherapy, and four (4.5 %) had clinical VTE of whom two developed VTE during chemoradiation, one during hospitalization for brachytherapy and one after completing treatment. Of the seven patients with VTE, two (28.6 %) were treated with hyperthermia. Adverse bleeding events after brachytherapy occurred in eight patients. CONCLUSION: Routine thromboprophylaxis in patients with LACC leads to a relative low incidence of thromboembolic events during chemoradiation and brachytherapy. Further research should focus on identifying high risk factors leading to targeted screening and prevention of VTE in high risk patients.