The present case-control study aimed to identify the main factors associated with colonization with carbapenemase-producing Klebsiella pneumoniae (CPKP) in acute care facilities. Administration of carbapenems (odds ratio [OR], 3.67; 95% confidence interval [CI], 1.37-9.83) and other antibiotics (OR, 2.83; 95% CI, 1.10-7.31) during the hospital stay was significantly associated with outcome. The design of this study, with concurrent selection of controls and matching by hospital ward and date of screening, provides a more accurate estimation of relative risks for CPKP colonization than previous investigations.