To identify risk factors for spontaneous rupture of liver abscess (SRLA), a retrospective study on patients with liver abscess caused by Klebsiella pneumoniae was performed. Of the 140 enrolled patients with liver abscess caused by K. pneumoniae, 8 (5.7%) experienced SRLA. In comparison to those with nonruptured liver abscess (NRLA), patients with SRLA were found to have significantly higher proportions of diabetic mellitus (100% versus 62.1%, P = 0.003), larger abscess size (mean of maximal diameter 7.8 versus 6.1 cm, P = 0.043), gas formation in abscess (87.5% versus 23.5%, P < 0.001), and left hepatic lobe involvement (50.0% versus 16.5%, P = 0.018). K. pneumoniae serotypes K1 and K2 were the predominant microorganisms isolated in both patients with NRLA and SRLA. Pulsed-field gel electrophoresis-generated fingerprinting of K. pneumoniae isolates from patients with SRLA revealed that these pathogens were nongenetically related.