In examining the relationship among nurse staffing, quality of care, and financial performance, prior empirical studies used competing measures and applied different levels of analysis. Using longitudinal data from 1990 through 1995, our study applied a dynamic econometric model to evaluate whether hospitals that changed their nurse staffing and quality of care affected their financial performance. Sampling 422 hospitals over this study period, we found a statistically significant increase in operating costs when registered nurse levels increase, but no statistically significant decrease in profit. Higher levels of non-nurse staffing caused higher operating expenses, as well as lower profits.