Implications and course of fever were evaluated during hospitalization of 24 patients with acute myelogenous leukemia. Forty-five febrile episodes were identified. Fever present at admission was usually associated with a diagnosable and treatable infection; fever shortly after induction was self-limited; and fever during granulocytopenia was more likely to be associated with bacteremia. Bacteremia and pneumonia were the most common types of infection. Only Gram-negative bacteria and Candida were identified as causes of infection during life, with Pseudomonas and Klebsiella the most frequently isolated pathogens. Invasive candidiasis was a major postmortem finding. A delay in initiation of empirical treatment beyond the third day of fever was associated with an increase in mortality as was continuation of treatment for longer than 14 days.