A retrospective analysis of 218 patients with gram-negative rod bacteremia was made in order to evaluate factors affecting survival of these patients. In patients with comparable underlying disease, no significant increase in mortality was found to be associated with race, sex, hospital service, level of leukocyte count, hospital-acquired infection, or the portal of entry of infection. Factors associated with an increased mortality from gram-negative rod bacteremia were shock, azotemia, Pseu-domonas bacteremia, and low or normal temperature during bacteremia. Appropriate antibiotic therapy significantly increased survival of all patients except those with the most severe underlying disease. A combination of antibiotics including colistimethate sodium, kanamycin sulfate, and penicillin, or its congeners, provided effective antimicrobial therapy against a higher percent of bacterial strains causing bacteremia than other drug regimens used during the period of this study.