Background: We aimed to study the possible beneficial effects of omega-3 polyunsaturated fatty acids (PUFAs) in carotid artery stenting (CAS) procedure for decreasing post-procedural ischemic complications. Although previous evidence demonstrated that omega-3 PUFAs, present in fish oil, can significantly enhance platelet response to antiplatelet agents after percutaneous coronary intervention (PCI), it is unknown whether they can be used in patients undergoing CAS.Methods: The single-blind, case-control, pilot randomized trial study was planned to perform on 60 patients undergoing CAS (30 in case and 30 in control group). Patients in both groups were pretreated with dual antiplatelet therapy (aspirin 80 mg/day with a loading dose of 325 mg, and clopidogrel 75 mg/day after a loading dose of 600 mg) at least 48 hours before the CAS. 30 patients randomly received 3000 mg loading dose of omega-3 fatty acids 12 hours before the procedure and 1000 mg omega-3 capsule the day after the procedure. All subjects were planned to be visited by neurologist for any peri- and post-procedural complications immediately after the procedure and on first, seventh, and thirtieth days.Results: We ended the study after the enrollment of 18 patients because of an unexpected hemorrhagic transformation in case group. Two patients in this group developed hemorrhagic symptoms less than 12 hours after the procedure. One of the failures occurred in a patient with small vessel disease. Except these two cases, no one showed any neurological deficit symptoms in both groups.Conclusion: In patients already receiving dual antiplatelet treatment before CAS, adding omega-3 PUFAs would increase the incidence of hemorrhagic transformation.