Continuous renal replacement therapy (CRRT) in critically ill patients has significant impact on one's ability to provide efficient nutritional therapy. CRRT may help in the prevention of intestinal oedema and the maintenance of the proper function of the gastrointestinal tract by enabling strict control of the fluid balance. It facilitates early introduction of nutrition via the enteral route, as well as allowing for the composition of high-volume feeding mixtures. It is necessary to take into consideration that during CRRT, together with blood purification of toxic substances, nutritive elements are also eliminated to some extent (micro-and macronutrients). In this article, the authors discuss the impact of CRRT on nutritive elements loss, energetic balance and present the principles of adjusting feeding prescriptions to changes implied by CRRT.Anaesthesiology Intensive Therapy 2017, vol. 49, no 4, 309-316 Key words: critical care, nutrition; kidney injury; continuous renal replacement therapy, energy requirements, protein needs Nutritional therapy is one of the basic elements of the multifaceted treatment of patients in intensive care units (ICUs). The Nutrition Day ICU survey, based on a seven-year observation period of nutritional practices in 880 units from 46 countries, has demonstrated that the majority of ICU patients do not receive the recommended amounts of calories and proteins [1]. According to the findings of this survey, as well as of some other studies, an increasing energy-protein deficit is positively correlated with prolonged ICU stay, which in turn increases the risk of infections and death. On the other hand, it should be clearly emphasised that an excessive energy supply may also be associated with complications and increased mortality [1,2]. Adequate tailoring of nutritional therapy is a great challenge; firstly, because the nutritional status of patients on admission to an ICU can differ markedly, ranging from cachexia to morbid obesity while secondly, the critical conditions presented by patients have extremely relevant metabolic implications. Unfortunately, the majority of studies that are the basis for guidelines of nutritional therapy are observational or involve small groups of patients and are therefore characterised by low precision and relatively high changeability over time.Several randomised controlled studies have recently been published which have re-started the discussion on optimal nutritional practices in the ICU setting. One of the issues inadequately described and connected with nutritional therapy in ICU patients, concerns the effects of other elements of the multifaceted treatment of critically ill patients on the efficacy of nutritional interventions. It should be clearly stressed that continuous renal replacement therapy (CRRT) belongs to those interventions which most highly affect the outcomes of nutritional therapy in critically ill pa-310 Anaesthesiol Intensive Ther 2017, vol. 49, no 4, 309-316 tients. Firstly, the use of CRRT facilitates optimal nut...