This paper explores the relationship between the cost and quality of hospital care from the perspective of applied microeconomics. It addresses both theoretical and practical complexities entailed in incorporating hospital quality into the estimation of hospital cost functions. That literature is extended with an empirical analysis that examines the use of 15 Patient Safety Indicators (PSIs) as measures of hospital quality. A total operating cost function is estimated on 2,848 observations from five states drawn from the period 2001 to 2007. In general, findings indicate that the PSIs are successful in capturing variation in hospital cost due to adverse patient safety events. Measures that rely on the aggregate number of adverse events summed over PSIs are found to be superior to risk-adjusted rates for individual PSIs. The marginal cost of an adverse event is estimated to be $22,413. The results contribute to a growing business case for inpatient safety in hospital services.