AIMS AND OBJECTIVES (i) To perform a nutritional screening using the Nutritional Form For the Elderly and relate the results to perceived health in a group of geriatric rehabilitation patients; and (ii) to compare the screening results and nurses' nutritional notes in the nursing documentation. BACKGROUND Undernutrition is an under-recognized problem among older patients. Using a screening instrument is a way to detect patients at risk for undernutrition. DESIGN A cross-sectional study conducted in Sweden. METHODS A sample of 147 geriatric rehabilitation patients was consecutively included and was interviewed with the screening instrument, questions about background variables, perceived health and health-related issues. Higher screening scores indicate higher risk for undernutrition. Parametric and nonparametric statistical tests were used. When nurses' nutritional notes in the nursing documentation were corresponding to the content in any of the response alternatives for each screening item, the notes were marked as existent. RESULTS The screening results showed that 55% of the patients were at medium risk and 14% at high risk for undernutrition. Patients in perceived ill health had higher screening scores than those in perceived good health. Associations were also found between receiving help, perceiving helplessness, not being active and not feeling satisfied and higher screening scores. The content of nine of 15 items in the instrument was mentioned in a number of nursing records. CONCLUSIONS The prevalence of older patients at medium or high risk for undernutrition was high. To be at high risk for undernutrition was associated with perceived ill health. Nurses' nutritional notes in the nursing documentation showed deficiencies, indicating that all patients at medium or high risk for undernutrition were not identified. RELEVANCE TO CLINICAL PRACTICE The results suggest that nurses need a screening instrument to highlight older nutritional at-risk patients in need of further awareness and investigation.