AIM: The aim of this study was to test the reliability and validity of the Nutritional Form for the Elderly (NUFFE). BACKGROUND: The prevalence of undernutrition among older people in nursing homes and hospitals reaches high levels. Assessment of older patients' nutritional status is an important task for nurses in clinical care. To use a simple nutritional assessment instrument for older people is one approach for nurses. Examples of such instruments are the well validated Mini Nutritional Assessment (MNA) and the newly developed NUFFE. METHODS: A total of 114 consecutively chosen, newly admitted older patients in an elder care rehabilitation ward in western Sweden were interviewed using the NUFFE and MNA. Arm and calf circumferences, body mass index (BMI), and presence of pressure sores and skin ulcers were noted as part of the MNA on admission. Weight was monitored and BMI calculated on discharge. Serum albumin levels on admission and discharge were used if these were available in the records. Reliability of the NUFFE was measured as homogeneity. Criterion related validity, concurrent validity, construct validity, and predictive validity were assessed with different statistical methods. The regional research ethics committee approved the study. RESULTS: The results showed that the NUFFE is a fairly reliable and valid instrument for identifying actual and potential undernutrition among older patients. CONCLUSION: The NUFFE is a simple tool for nurses to use to assess older patients with the aim of detecting undernourished individuals and those at risk for undernutrition. When doing a nutritional assessment with the NUFFE, the BMI ought also to be calculated. The assessment could also be combined with food intake recording for a period of time.