OBJECTIVES:  The Centers for Medicare and Medicaid Services (CMS) require public reporting of Clostridium difficile infection (CDI) rates as part of the Inpatient Quality Reporting Program. Under-performing hospitals may be at risk for significant financial penalties. This study evaluated incremental health care resource use and costs associated with potential misclassification of CDI. METHODS:  This was a retrospective, observational study of inpatient adults with a positive stool sample for Clostridium difficile from January 1, 2015 to March 31, 2016 at a community hospital. Patients were classified as definite community-onset CDI (positive stool sample within 3 days of admission) or healthcare facility-onset (positive stool sample at least 3 days post-admission). The healthcare facility-onset group was analyzed to identify symptomatic patients within 3 days of admission but had a ≥3 day delay in sampling stool for Clostridium difficile