Blood transfusion is a well-established treatment for anaemia. Herein, blood and its components are transfused to replenish circulating blood volume, maintain the oxygen capacity of the blood and normalise the function of the coagulation system. Anaemia treatment by blood transfusions is a great challenge, especially with reference to paediatric patients. Blood is irreplaceable in a life-threatening situation, but it has its own side effects, just like all applied pharmacological products. Hence, it is extremely important to carefully select donors and utilise blood components according to the patient’s individual needs. Children represent a group that requires specific criteria to be met, mainly because of the fact that their physiological and haematological systems differ from those of adults. The most common types of anaemia seen in children are deficiency anaemias such as iron-deficiency anaemia, while less common are vitamin B12 deficiency anaemia or folate deficiency anaemia. Secondary anaemia is also relatively frequent in chronic diseases, among others, immunological or infectious, as well as renal, liver, endocrine and neoplastic diseases. Anaemia due to blood loss is also included in this group. Furthermore, some anaemias, such as aplastic anaemia (due to impaired erythrocyte production) and haemolytic anaemia (due to excessive destruction of red blood cells) may be congenital or acquired. Before deciding to implement blood therapy, the patient’s clinical condition or the different haematological, biochemical and immunological parameters at different stages of life should be considered. Since each transfusion may result in a variety of post-transfusion reactions, immunisation or transmission of infectious diseases, the decision to transfuse blood or blood components should be taken only when the patient cannot be treated effectively by any other means and the expected benefits of the transfusion outweigh the risks associated with possible complications. Considering the recipients’ low blood volume, low metabolic efficiency, higher haematocrit levels than in adults and immature immune system, products for these patients should be prepared in a special way. These components must ensure minimal risk of metabolic and haemostatic disorders. The collection of these products, as well as their preparation, storage and transfusion, should be carried out in accordance with current legislation.