OBJECTIVE: To examine the prevalence of undernutrition in community-dwelling older individuals (>/=65 y) using data from various settings. METHODS: A cross-sectional observational study was performed to examine the prevalence of undernutrition in three samples (all >/=65 y): 1) 1267 community-dwelling individuals participating in a large prospective population-based study, the Longitudinal Aging Study Amsterdam (LASA) in 1998/99; 2) 814 patients receiving home care in 2009/10; and 3) 1878 patients from general practices during the annual influenza vaccination in 2009/10. Undernutrition was assessed by the Short Nutritional Assessment Questionnaire 65+. RESULTS: Mean age was 77.3 y (SD 6.7) in the LASA sample, 81.6 y (SD 7.4) in the home care sample, and 75.3 y (SD 6.5) in the general practice sample. The prevalence of undernutrition was highest in the home care sample (35%), followed by the general practice (12%) and LASA (11%) samples. The prevalence of undernutrition increased significantly with age in the general practice and LASA samples. Gender differences were observed in the general practice and home care samples; women were more likely to be undernourished in the general practice sample and men were more likely to be undernourished in the home care sample. CONCLUSION: The prevalence of undernutrition in Dutch community-dwelling older individuals was relatively high, especially in home care patients.