The high prevalence of anthropometric measurements and laboratory values that are similar to those in patients with protein-energy malnutrition has lead to the classification of a large number of dialysis patients as being malnourished. However, malnutrition in the strict sense implies that abnormalities will be reversed if more food is eaten. There is virtually no evidence, however, that simply providing more nutrients in the diet of dialysis patients will reverse the abnormalities attributed to malnutrition. This suggests that the diagnosis of malnutrition is a misdiagnosis. In this review, we discuss mechanisms that will cause the loss of protein stores, including albumin, other plasma proteins, and muscle mass in dialysis patients. We will also review the shortcomings of techniques that are used to measure the nutritional status of these patients.