Low dose aspirin has proven effectiveness in secondary and primary prevention of cardiovascular events and stroke, but is also associated with an increased risk of major bleeding events. For primary prevention, this absolute risk must be carefully weighed against the benefits of aspirin; such assessments are currently limited by a lack of data from general populations. Hemorrhagic complications associated with aspirin use occur primarily at skin or gastrointestinal sites and rarely in the central nervous system. In particular, spontaneous sternocleidomastoid hematoma associated with aspirin is very rare and has not been reported so far in the literature. We report a case of low–dose (75 mg daily) aspirin–related spontaneous hematoma of sternocleidomastoid muscle that was responded successfully of conservative management from taking off aspirin from the treatment schedule.