Gram-negative bacteremia is an important clinical syndrome in cancer patients because of its high morbidity and mortality. A total of 200 episodes of gram-negative bacteremia observed during the seven-year period between 1983 and 1989 in Hacettepe University Hospitals were studied to determine the clinical features and the factors influencing prognosis. The underlying malignancies were hematologic in 109 (54.5%) patients, lymphomas in 34 (17.0%), and solid organ tumors in 57 (28.5%). Granulocytopenia was observed in 120 (60%) episodes. Escherichia coli and Enterobacter-Klebsiella-Proteus species were isolated in 73 (36.5%) and 70 (35.0%) cases respectively, whereas Pseudomonas aeruginosa was the causative organism in 21 (10.5%). Hypothermia, shock, multi-organ failure and/or disseminated intravascular coagulopathy were observed in 72 episodes (36%). The overall mortality rate was 45.0%. Univariate analysis revealed that the presence of shock, multi-organ failure, and DIG were poor prognostic signs, whereas in multivariate analysis, shock and nosocomial infection significantly influenced the outcome. Thus, identification of prognostic factors may be useful in making necessary interventions other than appropriate antibiotic therapy and shortening the period of granulocytopenia in order to reduce the mortality rate.