Introduction: Risk factors for nosocomial carbapenem-resistant Klebsiella spp. (CRK) infections were analyzed in this study. Methodology: The incidence, clinical characteristics, risk factors, antimicrobial susceptibility, and outcomes of CRK infections during a seven-year period (2004)(2005)(2006)(2007)(2008)(2009)(2010) were retrospectively analyzed. Results: A total of 720 patients were included in the study. Carbapenem resistance among Klebsiella spp. was significantly increased between 2003 and 2007 (p < 0.001). CRK strains were mostly isolated from intensive care units (ICUs) (p < 0.001). Using imipenem and cefoperazone-sulbactam within the prior three months, staying in ICU, receiving immunspressive therapy, receiving H2 receptor antagonists, having a tracheostomy, using mechanical ventilation, hemodialysis, and having a urinary catheter were found to be significant risk factors for carbapenem-resistant Klebsiella spp. infections. In a multivariate analysis, previously using imipenem (OR 3.35; CI 1.675-6.726, p < 0.001), staying in ICU (OR 3.36;; p = 0.022), and receiving H2 receptor antagonist (OR 4.49; 95% CI 1.011-19.951; p = 0.048) were independently associated with carbapenem resistance. Respiratory tract infections were the most common nosocomial infections. Attack mortality rate was significantly higher in patients infected with CRK strains (p < 0.001). CRK strains showed significantly higher resistance rates to other antibiotics. Conclusions: The emergence and rapid spread of CRK strains in our hospital is worrisome. The patients in the ICU are at the highest risk for the acquisition of CRK strains. High resistant rates to other antibiotics except colistin and tigecycline limit therapeutic options, and increase mortality rates.