Uremic patients have been shown to be frequently malnourished. The amount of glucose absorbed from dialysis solution makes caloric malnutrition unusual among CAPD (Continuous Ambulatory Peritoneal Dialysis) patients. Protein malnutrition is more likely because of loss of nutrients into the dialysate and inhibition of appetite. Present study evaluates nutritional status of 29 patients (20 F, 9 M), 60.31 +/- 16.04, on CAPD since 15.2 months (4-50). Dialysis was scored adequate in all patients, based on the Clinical Assessment Score proposed by the Columbia University Group. Nutritional status was evaluated with (1) Marckmann score, based on relative body weight (RBW), triceps skin fold (TSF), midarm muscular circumference (MAMC), S-transferrin, and (2) Subjective Global Assessment (SGA) based on history, physical examination, anthropometric (BW, skin folds, % body fat according to Durnin, MAMC) and laboratory data (S-albumin, C3, S-transferrin, Hb, lymphocyte count, creatinine appearance rate [CAR], urea nitrogen appearance normalized by BW [NUNA], protein catabolic rate [pcr]). RBW was 118.2% because of excess stored fat; % body fat was > 40% in 6 females and 34.4 +/- 5 in 14 females. Lymphocytes, total proteins, S-albumin, S-transferrin, C3, IgG were normal. CAR (12.2 +/- 3.2 mg/kg/die) and NUNA (101.1 +/- 37.3 mg/kg/die) were lower than normal, as reported for dialysis patients. Marckmann score (26 patients) defined 10 cases of slight malnutrition; SGA (29 patients) identified 2 severely and 14 slightly malnourished patients. Marckmann and SGA scoring however agreed only in 13 over 26 patients. Slight or severe malnutrition has been assessed in CAPD patients in spite of clinically adequate dialysis.(ABSTRACT TRUNCATED AT 250 WORDS)