BACKGROUND: The healthcare burden of Clostridium (Clostridioides) difficile infection (CDI) is high but not fully characterized. AIM: To assess hospitalization costs, length of hospital stay (LOS) and in-hospital mortality attributable to CDI in the USA by analysing nationwide hospital discharge records over the 2012-2016 period. METHODS: A retrospective, observational study based on the Truven Health MarketScan Hospital Drug Database was conducted, in which 46,097 inpatient stays with a diagnosis of CDI were analysed. Costs, LOS and in-hospital mortality were studied for patients with either a principal or secondary (comorbidity) diagnosis of CDI, and for patients re-admitted because of CDI. If CDI was a comorbidity, its attributable burden was estimated by coarsened exact matching, comparing 17,273 CDI stays with 84,164 stays in a control group without a CDI diagnosis. FINDINGS: Inpatients for whom CDI was the main reason for hospitalization incurred mean costs of US$10,528 and an average LOS of 5.9 days. For CDI as a comorbidity, the mean additional cost was US$11,938 and the additional LOS was 4.4 days. CDI also increased the in-hospital mortality rate by 4.1%, on average. CONCLUSION: This study is consistent with previous publications which demonstrated the high economic burden of CDI for healthcare settings and health insurance systems. When recorded as a comorbidity, CDI significantly increased hospital costs and LOS. These results highlight the need for innovative therapeutic approaches in the prevention and treatment of CDI.