Protein requirements in maintenance hemodialysis patients are still unclear. Based on nitrogen balance studies and different analyses of protein and amino acid metabolism, the recommendations until recently were 1 g/kg of body weight, primarily of high biological value protein. According to the results of controlled long-term studies the 1 g recommendation now seems too low. The paper reports on the results of a controlled study undertaken to define protein requirements. The effect of supplementation with a special protein mixture is studied on the basis of 1 g of protein per kilogram of body weight intake and about 20 hr standard dialysis per week. The results suggest that 1.2 g of protein per kilogram of body weight primarily of high biological value protein and 35 kcal/kg of body weight should be prescribed for dialysis patients. In case of complications (bleeding, infection, and other stress situations) additional supplements are necessary.