To determine the usefulness of a clinical data repository for nursing, we conducted two studies (1) investigating the gaps between required nursing care time based on patient classification and actual nursing care time based on nurse staffing level and (2) exploring the practice variations of nurses by comparing nursing interventions documented to prevent and treat pressure ulcers. We reviewed the nursing records of 124 416 patients discharged from 2005 to 2007 to identify the gaps in nursing care time. We also reviewed records of 41 891 patients discharged in 2007 to identify those who had pressure ulcers or were at risk of pressure ulcers and analyzed the nursing interventions documented to prevent and treat pressure ulcers. The pediatric and geriatric units showed relatively high staffing needs and the trends of understaffing over time. For pressure ulcer care, nursing interventions vary by nursing unit. Position change was the most common nursing intervention documented except in the maternity unit, followed by ulcer wound care, use of devices, and nutritional assessment. This study showed that data in a clinical data repository can provide nurse managers and nurses with valuable information about nurse staffing and patient care.