Intramuscular hemorrhages and hematomas are a complication of anticoagulation in patients using warfarin as an anticoagulant. Hematomas may be due to trauma or may develop spontaneously. Neuropathies due to direct compression of hematomas or hemorrhage around the nerve may rarely occur. We aimed to present a case of spontaneous hematoma in the triceps muscle and associated radial nerve deficit in a patient taking warfarin for valvular disease. The hematoma was evacuated after prothrombin complex concentrate and vitamin K. The patient’s nerve deficit improved in the follow-up. Early evacuation of the haematoma may be important for favorable outcomes.