To determine in primary care the nutritional status of elderly people at risk of malnutrition and to evaluate their evolution after an intervention. Descriptive, with follow-up. Urban health centre. Patients over 65, with criteria as fragile elderly or incapacitated and registered on a doctor's list (N=131). Nutritional risk factors were identified in the consultation or at home in 46 of those included in the study (March-September 2003). Age, sex. Factors in risk of malnutrition: loss of weight, acute or chronic illness associated with malnutrition, social factors. Anthropometric indices: Body Mass Index (BMI), tricipital fold (TF) and percentage, brachial perimeter (BP), calf perimeter (CP), arm muscular circumference (AMC), and percentage. Analytic indices: lymphocytes, transferrin, albumin. Malnutrition: when at least 2 of the above parameters were disturbed. Type: calories, protein, mixed. Degree: light, moderate, or severe. special diets and/or nutritional supplements. Parameters were re-assessed at 6 months (t test, paired samples). Average age of 83, with 63% women. Nutritional risk factors: loss of weight 41%, acute illness 39%, chronic illness 10.5%, cognitive deterioration 4%, social risk 2%. 80.4% suffered malnutrition (32.5% calories, 46% mixed, 21.5% protein; 27% light, 56.7% moderate, 16.3% severe). Mean values on anthropometric parameters: BMI 21, TF 11.3 mm (TF% 72%), BP 22 cm, AMC 19.4 (%AMC 90%), CP 28 cm (%CP 87%). Mean analytic values were: transferrin 243, albumin 3.7, lymphocytes 1600. Nutritional supplements were indicated in 11 cases. 32 cases were re-evaluated later and no significant improvement was found for any parameter (=.05). Malnutrition is common in the elderly with risk factors (loss of weight and acute illness), with calorie or mixed malnutrition the most common kinds. There was no improvement in anthropometric parameters at 6 months follow-up.