In the period 1988-1993, 241 patients had Klebsiella bacteraemia at our medical centre. The annual number of patients with positive blood cultures increased from 306 in 1988 to 622 in 1993, representing a 4.5-6% positivity rate of drawn cultures. After E. coli, Klebsiella was the leading cause of Gram-negative bacteraemia. During this period, the absolute number of Klebsiella bacteraemia increased from 25 in 1988 to 84 in 1993; this represents a true increase in Klebsiellaa bacteraemia, from 6-7% of positive cultures in the late 1980s to 12-13% in more recent years. There were 210 cases with K. pneumoniae and 31 with K. oxytoca. A representative sample of 80 records was retrieved and subdivided into two groups: community-acquired Klebsiella bacteraemia (CAKB) vs. hospital-acquired Klebsiella bacteraemia (HAKB). Urinary tract infection was the underlying source of 58% of CAKB vs 28% of HAKB (p < 0.01); pneumonia occurred significantly more often in HAKB (25%) than in CAKB (7%) (p < 0.01). In HAKB, as compared to CAKB, serious manifestations of illness were more common, e.g. shock (65% vs. 37%, p < 0.046) and respiratory failure (45% vs. 20%, p < 0.046). Overall mortality was 32%, 22% of patients with CAKB died vs. 42% of those with HAKB (p < 0.05). Multiple drug resistance was very common: only 57% of all Klebsiella strains were susceptible to gentamicin, 66% to ceftriaxone, 70% to ciprofloxacin, and 83% to amikacin. The susceptibility rates of Klebsiella spp isolated from patients with HAKB were significantly lower (p < 0.001). Sepsis due to multiple-drug-resistant Klebsiellaa has become frequent, carrying significant morbidity and mortality. Restriction of broad-spectrum antimicrobials in the hospital and the community as well as implementation of infection control measures are needed to contain this problem.