Malignant diseases in childhood are the second leading cause of death of children between the ages of 0 and 15, right after accidents. The most common malignant diseases in childhood are acute lymphoblastic leukemia, brain tumours, lymphoma and sarcoma of soft tissue and bone, as opposed to malignant diseases in adulthood, such asepithelial tumours in the form of lung cancer, prostate cancer and large colon cancer. Malignant diseases in childhood have many social and medical consequences, because they can traumatize the children, create difficulties in overcoming the new situation they're in and significantly affect the family of the child. There are three main ways of treating tumours: surgical treatment (the tumour is removed through an operation), using certain drugs (cancer cells are being destroyed with the use of drugs: chemotherapy or antitumor drugs, immunotherapy, focused therapy of new drugs), radiotherapy (cancer cells are being destroyed with radiation). During the treatment it is of great importance to use multidisciplinary approach, in other words utilizing the most of the treatment which can benefit the child and the family. Because of the number of newly diagnosed children, which includes a very specific nursing care, it is of great importance to provide a high-quality approach to nursing care. Nurses and other healthcare personnel act as a multidisciplinary team, that do not only act towards healing the child, but also provide support to both the childband the family: they provide necessary information, advise them in the decision-making process, give emotional support both during and after treatment. The purpose of this thesis is to raise awareness in the Republic of Croatia about the many problems children with malignant diseases, and their parents face, and to point out the critical faults during nursing care process, in order to recognize and eliminate them in time, if possible.