Disorders of coagulation can be inherited or acquired and can result in abnormal bruising or bleeding. Affected children may have significant morbidity or mortality if one of these disease processes goes unrecognized or is not treated appropriately and expeditiously. Any child presenting to the emergency department with bruising or bleeding should receive a careful physical examination to determine if the presentation correlates with history provided and to assess for nonaccidental trauma. Detailed personal and family history of easy bruising, bruising out of proportion to injury, or prolonged bleeding after minor procedures may aid the elucidation of a coagulation defect. This article discusses 3 cases of bleeding diathesis presenting in the emergency department, with a review of basic pathophysiology, initial evaluation, and management. Together, they are representative of the types of bleeding mechanisms to consider, although they do not represent all disorders which clinicians may encounter throughout their clinical work.