BACKGROUND Malnutrition has been strongly associated with morbidity and mortality in hemodialysis patients. In the other hand, dialysis allows a nutritional improvement in patients with more than 12 months in dialysis. OBJECTIVE To study the prevalence of malnutrition among patients in hemodialysis. METHODS We measured clinical, anthropometric and biochemical parameters of nutritional status in chronic hemodialysed patients. Results were related to individual time in dialysis. Patients with more and less than 12 months in dialysis were compared. RESULTS Twenty nine patients (18 male) aged 14 to 65 years old, were studied. Mean caloric intake was 23.8 Cal/Kg and protein intake was 0.7 g/Kg. Mean body mass index was 21.7 +/- 3.7 kg/m2 Thirty eight percent of patients had a body mass index of less than 20 kg/m2. Mean serum albumin was 4.1 +/- 0.7 g/L; mean prealbumin was 33.5 +/- 7.9 mg% and creatinine was 9.6 +/- 2.8 mg%. Serum cholesterol was 182 mg% and triacylglycerol 129 mg%. PCR was 42.2 +/- 18.8 and Kt/V was 1.45 +/- 0.3. We did not find a correlation between nutritional markers and time in dialysis or a difference in nutritional parameters between patients with less or more than 12 months in dialysis. CONCLUSIONS These patients in chronic dialysis have a high prevalence of caloric malnutrition, which may be due to a poor caloric intake. Protein malnutrition parameters were normal in most patients. The absence of abnormal lipid levels, common in chronic renal failure, is noticeable.