The purpose of this study was to identify risk factors for mortality in neutropenic patients with cancer and bacteremia. A consecutive sample of 438 neutropenic patients (granulocyte count <0.5 x 10(9)/l) with cancer and bacteremia was studied to identify the clinical characteristics associated with mortality at the onset of bacteremia. The mean age of the subjects was 48 years (range, 15-87 years). Most cases of bacteremia (77%) were hospital-acquired and occurred in patients with acute leukemia (48%). Gram-positive organisms caused 233 (53%) episodes of bacteremia, gram-negative organisms caused 151 (34%) episodes, and 48 (11%) episodes were polymicrobial. The overall mortality within 30 days of the onset of bacteremia was 24.4%. The variables found to be independently associated with increased mortality using logistic regression techniques were as follows: shock at the onset of bacteremia (OR, 10; 95% CI, 4.2-23.8), pneumonia (OR,4.4; 95% CI, 1.9-10), uncontrolled cancer (OR,4.3; 95% CI, 1.5-12.7), and absence of prophylaxis with norfloxacin (OR,2.4; 95% CI, 1.3-4.5). The prognostic factors ascertained in this study may help to identify those patients at higher risk of death. Medical intervention addressing some of these factors may improve the outcome of bacteremia in neutropenic patients with cancer.