The present study was designed to test the hypotheses that there would be physical, affective, and cognitive function decline from baseline at 3 months and 6 months for the total group and within age groups and that decline would be predicted by nutritional status. Serum concentrations of albumin, cholesterol, hemoglobin, and percent lymphocytes and white blood cells (to calculate total lymphocyte count) were measured; fat reserves and somatic protein were estimated from anthropometry; and physical signs of malnutrition and a composite of nutritional status indicators were assessed. The participants in the 6-month longitudinal study were females and males aged 75-96 years (N = 132). Physical function was measured by the Physical Self Maintenance Tool (PSMT), the Instrumental Activities of Daily Living (IADL) scale, and the Tinetti Balance and Gait Evaluation to assess decline. Affective function was measured by the Geriatric Depression Scale (GDS). Cognitive function was measured by the California Verbal Learning Test (CVLT). Where decline was significant (p ≤ .05), nutritional parameters were used to predict (p ≤ .10) decline in this exploratory research. Logistic regression revealed physical decline in balance and gait which was predicted by high or low total lymphocyte counts and low fat reserves. Aspects of cognitive decline were predicted by low fat reserves; by combined low fat reserves, low albumin, low cholesterol, and low Mini Nutritional Assessment scores; and by combined high fat reserves and high cholesterol.