This report reviews 196 episodes of klebsiella bacteremia in 194 patients during a 10-year period (1980-1989) in a community teaching hospital in the USA. The median age of patients was 70 years with a mode of 84 years. The prevalence was 0.76 episodes/1000 admissions. Nosocomial acquisition of bacteremia occurred in 43% of episodes and 16% of patients were from nursing homes. Klebsiella pneumoniae accounted for 86% and K. oxytoca for 13% of episodes. Most isolates were resistant to ampicillin and carbenicillin but susceptible to other antimicrobial agents tested. 55 episodes (28%) were polymicrobial; Escherichia coli and enterococci were the most common co-isolates. The major portals of entry were the respiratory tract and urinary tract. The majority of patients had major underlying conditions. The overall mortality was 37%. Factors that adversely influenced the mortality rate were nosocomial bacteremia, polymicrobial bacteremia, respiratory tract as the portal of entry, rapidly fatal and ultimately fatal underlying conditions, septic shock, severe leukopenia, increases in total serum bilirubin level or serum creatinine level and inappropriate antimicrobial therapy.