This Statistical Brief presents data from the Healthcare Cost and Utilization Project (HCUP) on costs of hospital inpatient stays in the United States using the 2017 National Inpatient Sample (NIS). It describes the distribution of costs by primary expected payer and illustrates the conditions accounting for the largest percentage of each payer’s hospital costs. Hospital charges were converted to costs using HCUP Cost-to-Charge Ratios. The expected payers examined are Medicare, Medicaid, private insurance, and self-pay/no charge. Because of the large sample size of the NIS data, small differences can be statistically significant. Thus, only differences greater than or equal to 10 percent are noted in the text. Hospital costs in this Statistical Brief represent the hospital’s costs to produce the services—not the amount paid for services by payers—and they do not include separately billed physician fees associated with the hospitalization.