[Excerpt fron publisher]Background. Little research has been conducted that examined the intended effects of nursing care on clinical outcomes. Objective. The objective of this study was to evaluate the impact of different nurse staffing models on the patient outcomes of functional status, pain control, and patient satisfaction with nursing care. Research Design. A repeated-measures study was conducted in all 19 teaching hospitals in Ontario, Canada. Subjects. The sample comprised hospitals and adult medical-surgical and obstetric inpatients within those hospitals. Measures. The patient's functional health outcomes were assessed with the Functional Independence Measure (FIM) and the Medical Outcome Study SF-36. Pain was assessed with the Brief Pain Inventory and patient perceptions of nursing care were measured with the nursing care quality subscale of the Patient Judgment of Hospital Quality Questionnaire. Results. The proportion of regulated nursing staff on the unit was associated with better FIM scores and better social function scores at hospital discharge. In addition, a mix of staff that included RNs and unregulated workers was associated with better pain outcomes at discharge than a mix that involved RNs/RPNs and unregulated workers. Finally, patients were more satisfied with their obstetric nursing care on units where there was a higher proportion of regulated staff. Conclusions. The results of this study suggest that a higher proportion of RNs/RPNs on inpatient units in Ontario teaching hospitals is associated with better clinical outcomes at the time of hospital discharge.