Bacteremic pneumonia due to aerobic gram-negative bacilli was diagnosed in 27 patients during a 20-month period. The mortality was high (81.5%) among these elderly patients (mean age, 61.2 years) with serious underlying disease, in spite of amikacin sulfate therapy that was appropriate as determined by susceptibility testing. Bacteremic pneumonia accounted for 14.1% of patients with gram-negative bacteremia but was responsible for 39.4% of the deaths in the total group of 191 patients. The worsened prognosis of patients with pneumonia was unrelated to the species of infecting organisms or the underlying conditions or disease.