Epistaxis is one of the most frequent emergencies in rhinology. Patients using anticoagulative medication are at increased risk for epistaxis. We evaluated the prothrombin time and the international normalized ratio (INR) in anticoagulated epistaxis patients. Patients suffering from epistaxis were prospectively included in a database and results from prothrombin testing were analyzed in the context of anticoagulation. One hundred sixteen of 591 epistaxis cases were identified to be on oral anticoagulation. The INR was found to be above therapeutic levels in 19 (16%) of these cases. We strongly recommend prothrombin time and INR testing in all epistaxis patients taking any sort of vitamin K antagonists.