Elderly individuals are at risk for acute confusion (AC) during hospitalization. Using a prospective design, this study assessed the relationship between admission risk factors and subsequent development of AC in 117 elderly hospitalized patients. AC was ascertained using the NEECHAM Confusion Scale. Other measures included demographic data, cognitive status, physical function, laboratory data, medications, infections, activity, pain, and nursing acuity. The cumulative incidence estimate was 14%. Patients who developed AC were more likely to be admitted to the hospital from somewhere other than home, to have lower admission NEECHAM and MMSE scores, and to have restricted activity levels, an infection, and abnormal lab values. These patients were more cognitively and physically frail and may have been chronically undernourished and dehydrated on admission to the hospital. Nurses can be trained to routinely assess for acute confusion using easily implemented instruments incorporated into a research-based protocol.