An attempt was made to see if new forms of treatment of fungal and bacterial septicemia, or new cytostatic combinations have changed the causes of death in leukemia and lymphoma. Autopsies were studied of 16 cases with acute leukemia, 2 with chronic granulocytic leukemia and 24 with lymphoma. 10 of the 18 patients with leukemia and 10/24 lymphoma patients died although they had no, or only slight, tumor infiltration in the bone marrow and parenchymatous organs; only 1/18 leukemias had extensive infiltration. There was a statistically significant correlation between the extent of marrow andorgan infiltration. Cardiac failure (5/18 patients) was almost as common as the main cause of death as septicemia (7/18) in leukemia. The corresponding figures in lymphoma were5/24 and 9/24, respectively. The present findings contrast with earlier ones, where more septicemia and tumor infiltration were found at autopsy, and less cardiac failure was observed. 15 of 16 cases with septicemia at autopsy had terminal fever. Bacteriological and histological signs of septicemia at autopsy agreed satisfactorily. There was a suprising absence of agreement between terminal granulocytopenia and septicemia; 13 of 16 patients with septicemia had over 0.1 × 109 and 10 over 0.5 × 109 granulocytes/liter blood.