To determine the clinical significance of Kluyvera isolates at our institution, we retrospectively analyzed clinical microbiology data from January 1999 to September 2003. We identified 11 isolates classified as Kluyvera ascorbata, 7 of which were considered clinically significant pathogens: 3 cases represented urinary tract infections; 2, bacteremia; 1, a soft tissue infection of the finger; and 1, acute appendicitis with a subsequent intra-abdominal abscess. The age distribution of patients was wide, ranging from 2 months to 73 years. Antimicrobial susceptibility studies of the clinically significant and non-clinically significant Kluyvera isolates showed susceptibility patterns similar to those reported in the medical literature, namely trends of resistance to ampicillin and first- and second-generation cephalosporins. Of the 4 non-clinically significant isolates in our study, 1 was resistant to ciprofloxacin, a finding reported in only 1 other isolate of Kluyvera in the medical literature. Patient outcome after treatment with third-generation cephalosporins and aminoglycosides in the 7 clinically significant cases was good, with no long-term sequelae. The potential virulence of K ascorbata highlights the need for heightened scrutiny of its antimicrobial susceptibility patterns for adequate clinical treatment.