Background: The quantitative effect of multidrug-resistant bacterial infections on real-world health care resources is not clear. This study aimed to estimate the burden of methicillin-resistant Staphylococcus aureus (MRSA) infections in pneumonia inpatients in Japan. Methods: Using a nationwide administrative claims database, we analyzed pneumonia patients who had been hospitalized in 1,063 acute care hospitals. Patients who received anti-MRSA drugs were categorized into an anti-MRSA drug group, and the remaining patients comprised the control group. We estimated the burden of length of stay, in-hospital mortality, total antibiotic agent costs, and total hospitalization costs. Risk adjustments were conducted using propensity score matching. Results: The study sample comprised 634 patients administered anti-MRSA drugs and 87,427 control patients. In propensity score-matching analysis (1 to 1), the median length of stay, antibiotic costs, and hospitalization costs of the anti-MRSA drug group were significantly higher than those of the control group (21 days vs 14 days [P < .001], $756 vs $172 [P < .001] and $8,741 vs $5,063 [P < .001], respectively); the attributable excess of these indicators were 9.0 +/- 1.6 days, $1,044 +/- $101, and $5,548 +/- $580, respectively. Conclusions: These findings may serve as a reference to support further research on multidrug-resistant bacterial infections and eventually inform policy formulation. (C) 2016 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved.