Total parenteral nutrition (TPN) is still of great importance for haematopoietic stem cell transplantation (HSCT) patients because one of the major adverse effects of the high-dose therapy followed by HSCT is an inadequate oral nutrition intake. The aim of the study was analysis of TPN of young patients in the HSCT period. Twenty-two patients 1.8-20.8 year-old, median 5.4, treated with high-dose therapy and autologous HSCT because of malignancy were included into the study. Grafts contained 1.35-7.9 x 106, median 3.75 x 106 CD34+ cells/kg. Engraftment occurred as follows: granulocytes >0.5 x 109/l on +11 d (8-25); platelets >20 x 109/l on +23 d (12-67). Patients were given isoenergetic, isonitrogenous TPN until they consumed less than 50 % of their required diet orally. Proteins intake was 0.8-2.0 g/kg per d, fats intake 1.0-3.0 g/kg per d. Total non-proteins energies-nitrogen grams index was 140:1-200:1. Supplementation of electrolytes, microelements, trace elements and vitamins was dependent on individual patient requirement. TPN duration did not correlate with CD34+ cells number but correlated with platelets reconstitution. The assessment of nutritional condition demonstrated no differences in anthropometric parameters, but increase of serum albumin levels after TPN. Requirement for P3 - was above the normal ranges and correlated positively with platelets reconstitution. Requirement for P3 - and K+ was higher in patients with mucositis than in other patients. Any complications due to TPN were observed. Adequately composed isoenergetic and isonitrogenous TPN with replacement of electrolytes according to their requirement in the early post-transplantation period allows not only improvement in nutritional status of patients but also could contribute to reconstitution of haematopoiesis.