Hematologic emergencies are bleeding or clotting disorders that must be treated emergently to avoid significant morbidity or mortality. Hematologic emergencies can be hereditary or acquired and subdivided into bleeding, clotting, or combined disorders. This article covers selected hematologic conditions that require urgent evaluation. Bleeding emergencies present with clinical symptoms and often significant laboratory findings such as thrombocytopenia (platelets less than 10 × 10³ per μL), elevated international normalized ratio [INR], or anemia with evidence of hemolysis (Table 1^1–4). Blood product transfusions, including platelets, packed red blood cells (RBCs), cryoprecipitate, and factors VIII, IX, or VII, are critical in treating bleeding emergencies (Table 2).^5–7 Corticosteroids, monoclonal antibodies, intravenous immunoglobulin (Ig), and exchange transfusions may be needed for acquired hematologic emergencies, in addition to blood products. During a potential hematologic emergency, a hematologist referral should be considered when active bleeding requires the administration of hemostatic products, abnormal findings on initial blood level testing cannot be easily explained, or an acute hematologic malignancy is suspected.