PURPOSE: To analyse the clinical features and CT findings of pyogenic liver abscess due to Klebsiella pneumoniae, and to compare the findings with those of cases in which abscesses were caused by other pathogens. MATERIALS AND METHODS: Twenty-one cases of pyogenic liver abscess were assigned to either the Klebsiella or the non-Klebsiella group, and the patients' past medical history and intra-abdominal abnormalities such as calculus or malignancy were reviewed. Laboratory data such as alkaline phosphatase (ALP), SGOT and SGPT levels were analyzed, and on the basis of the CT findings, decisions were reached as to (a) whether abscesses were single or multiple, multiple contiguous or discontiguous, uniloculated or multiloculated; and (b) the presence or absence of gas, hepatic parenchymal enhancement, peripheral rim enhancement, and extrahepatic abnormality. For statistical analysis, Fisher's exact test was used. RESULTS: Among 21 abscesses, Klebsiella pneumoniae was the most common pathogen (n=11). The others were Pseudomonas (n=3), E.coli (n=2), Enterococcus (n=2), G. (+) cocci (n=2) and Polymicrobial (n=1). Diabetes mellitus was more common among patients in the Klebsiella group, among whom a multiloculated single cavity was a frequent finding. Five patients in the non-Klebsiella group experienced biliary tract obstruction, which was not demonstrated in the Klebsiella group. Hepatic parenchymal enhancement was more common in the non-Klebsiella group. CONCLUSION: In cases of pyogenic liver disease, especially where diabates mellitus is involved, Klebsiella pneumoniae is a major pathogen. Significant CT findings of Klebsiella liver abscess included a multiloculated single cavity, rare biliary tract obstruction, and little hepatic parenchymal enhancement.