Four cases of fulminant pneumococcal septicemia in splenectomized patients are reported. Three had undergone splenectomy for trauma 42, 28 and 14 years prior to the septicemia. The fourth had been splenectomized for suspected lymphoma 3 years earlier. In 3 out of 4 patients the symptomatology was so rapidly progressive that a physician was consulted within 12 hours. Two patients hospitalized after a second consultation and 20 hours after the first symptoms had evidence of septic shock, disseminated intravascular coagulation and hypoglycemia, and died within a few hours despite early antibiotherapy. Diplococci were seen in peripheral smears of these 2 patients and in the buffy coat of the 3 cases in which this was carried out. These four cases reemphasize the fact that during their entire life splenectomized patients are at risk for development of overwhelming septicemia even when the splenectomy was performed because of trauma. Therefore, such patients should be aware of this risk, should be treated promptly with antibiotics in the event of a febrile episode, and should be vaccinated against pneumococci and possibly other encapsulated bacteria such as Haemophilus influenzae and Neisseria meningitidis.