Evaluation of the Caring Assessment Tool (CAT) is essential for its use in the monitoring and ongoing improvement of patient–nurse relationships. This descriptive, prospective study evaluated the dimensionality and internal reliability of the instrument in a sample of hospitalized adults. In addition, reduction of items was achieved, lessening clinical and administrative burden. Data were collected from 1,111 patients in 12 U.S.hospitals in 4 geographically distinct regions. A single factor explained 73% of the variance in the construct and the number of items was reduced to 27. Internal consistency remained high (a = .97). Patient–nurse relationship data were collected safely and efficiently from hospitalized patients using a paper-and-pencil approach. The CAT holds promise for providing acute care registered nurses with the information they need to deliver reliable patient-centered care.