An increasing number of elderly patients with uraemia are treated by dialysis therapy. Virtually every published study on nutritional status of patients undergoing maintenance haemodialysis treatment or continuous ambulatory peritoneal dialysis (CAPD) has indicated that a substantial proportion of patients undergoing regular dialysis treatment have protein calorie malnutrition. Problems of undernutrition increase significantly with age; a combination of socioeconomic, psychological, and biochemical problems interfering with acquiring and assimilating a balanced diet are responsible for nutritional deficiencies in older people. We assessed the prevalence of protein calorie malnutrition in 183 regular dialysis patients aged 65 years or older treated with haemodialysis or CAPD. This group of patients was compared to two other groups aged 18-40 years (62 patients) and 41-64 years (239 patients). Presence of malnutrition was assessed by selected serum chemistries, anthropometry and Subjective Global Nutritional Assessment. Adequacy of dialysis, protein nitrogen appearance, as an index of protein intake, and residual renal function were measured. The results indicate that protein calorie malnutrition occurs commonly in regular dialysis patients, with a higher prevalence of malnutrition in the elderly; 51% of patients of the elderly group were classified as malnourished, and no difference was found with the two dialytic modalities.