A long-term follow-up of 740 American servicemen splenectomised because of trauma during the 1939-45 war showed a significant excess mortality from pneumonia and ischaemic heart-disease. Mortality from cirrhosis was also increased, but not significantly. The findings confirm that the risk of fatal infections is increased by asplenia; however, the risk of cancer was not increased, as it is in some other immunodeficiency states. Post-splenectomy thrombocytosis and hypercoagulability may account for the increased risk of fatal myocardial ischaemia in this group.