This chapter discusses the diagnosis, evaluation and management of disseminated intravascular coagulation and thrombotic thrombocytopenic purpura (TTP)/hemolytic uremic syndrome (HUS). The classic presentation of TTP involves a pentad of symptoms that include fever, neurological signs, anemia, thrombocytopenia, and renal dysfunction. This collection of symptoms is only seen in 20-30% of cases and it is strongly recommended to suspect the condition and manage it as such if a patient exhibits three or more of those features. HUS is most commonly seen in children and often follows an infectious illness, usually diarrhea. Morbidity and mortality in patients with TTP/HUS are usually attributed to thrombosis rather than anemia and bleeding. Patients with TTP can present with neurological symptoms that can be life threatening themselves or complicated by a life-threatening event. Patients (usually children) presenting with HUS may have significant renal dysfunction requiring dialysis.