The calculation of body composition using bioelectrical impedance analysis is difficult in the elderly because most equations have been found to be inadequate, especially in the malnourished elderly. We therefore evaluated the use of bioelectrical impedance vector analysis in elderly nursing home residents.One hundred twelve nursing home residents were included in the study (34 men, 78 women, age 85.1 y, age range 79.1-91.4 y). Nutritional status was determined by the Mini Nutritional Assessment (MNA), functional status was assessed by handgrip strength, knee extension strength, and Barthel's index, and bioelectrical impedance analysis was performed using Nutriguard M (Data Input, Darmstadt, Germany).Twenty-two nursing home residents were classified as well nourished (MNA I), 80 were considered to be at nutritional risk (MNA II), and 10 were classified as malnourished (MNA III). Handgrip strength, knee extension strength, and Barthel's index were lower in MNA II and MNA III than in MNA I. Phase angle also decreased significantly with the MNA (4.0, 3.8-4.7 degrees; 3.7, 3.3-4.3 degrees; and 2.9, 2.6-3.5 degrees). There was a significant displacement of the mean vector in MNA II and MNA III compared with MNA I.The bioelectrical impedance vector analysis resistance/reactance graph could represent a valuable tool to assess changes in body cell mass and hydration status in elderly nursing home residents.