Introduction: One of the biggest concerns associated with endovascular procedures is the development of thromboembolic events. To mitigate this risk, patients are placed on dual antiplatelet therapy. Interestingly, there is a known variation in one’s ability to appropriately respond to antiplatelet medications and patients with decreased responsiveness may be at an increased risk of developing ischemic complications. Routine testing of antiplatelet responsiveness is not performed at most endovascular centres and is still a topic of controversy within the neurosurgical community. The objective of our study was to determine if non-responsiveness to aspirin and clopidogrel was associated with the development of symptomatic thromboembolic events in patients undergoing cerebrovascular stenting procedures. Methods: A prospective study was conducted at the Foothills Medical Centre in Calgary, Alberta, Canada from August 2019 to February 2021. Patients undergoing cerebrovascular stenting procedures and who were on dual antiplatelet therapy consisting of aspirin and clopidogrel were enrolled in the study. Responsiveness to the antiplatelet medications was determined through whole blood impedance aggregometry and the treating neurointerventionalists were blinded to these results. The primary outcome was the development of a symptomatic thromboembolic event at 90 days after the procedure. Demographic, clinical, radiological, and procedural variables were analyzed to determine which factors were associated with the development of thromboembolic events. Results: One hundred and eighteen procedures were performed in 115 patients. The non-response rate of clopidogrel and aspirin was 21% and 14%, respectively. There were 12 (10%) thromboembolic events that occurred during the study period. On the univariable analysis age (p=0.03) and non-responsiveness to clopidogrel (p=0.01) were associated with the development of thromboembolic events, while aspirin non-responsiveness was not (p=0.13). On the multivariable logistic regression only clopidogrel non-responsiveness (OR 3.91, 95%CI 1.05, 14.50, p=0.04) was associated with the development of thromboembolic events. Conclusion: Our study has demonstrated that patients who were identified as clopidogrel non-responders, using whole blood impedance aggregometry, were at an increased risk of developing thromboembolic events. Furthermore, the results of our study validate the need for larger observational studies or randomized controlled trials to assess the utility of platelet function testing prior to cerebrovascular stenting procedures.