Treating malignant diseases in adolescents is a complex and long-term process that lasts several months or sometimes years with persistent of disease relapse. Determining priorities begins with detecting a diagnosis, therefore the participation of patients in planning health care and self-care is of great importance in order to preserve dignity and self-esteem. Young people in this period of life are often confused and frightened, especially when fall ill of severe malignant diseases, pass through extremely difficult life situations. It appears an anxiety and sadness due to the interruption of habitual lifestyle and changes in life plans. Nurse care for such patients means an interactive relationship in the treatment process. The emphasis of care is on a holistic approach, especially because the age of adolescence is considered a dynamic developmental period. Psychological space is unstable most of all because the status of an adolescents is double: one part are children and the other are adults. Passing through the various stages of adolescence young people try to get to know themselves and to accept the condition in which they are. Ill adolescents often change their image of themselves because of the situation they found themselves and try to balance between the environment and themselves. It is very important to establish a relationship of trust and safeness with ill adolescent and his/her family. After diagnosed, adolescents who lived their youthful lives until yesterday suddenly find themselves in a life-threatening situation. Sudden changes in their lives tends to compensate through many defensive mechanisms, and if they fail to overcome, occurs emotional and psychological disorders that can leave long-lasting consequences if they do not recognize it in time. Using aggressive forms of therapy results in distortion of outside appearance of the patient, which additionally disturbs the self-perception of the patient. In addition to the multidisciplinary team involved in treating adolescents, parents have a key role to play in supporting their child to overcome the disease with the less negative effects as possible. Discussion about the disease within the family is associated with a lower risk of developing depressive disorders in adolescents and strengthening self-confidence as well as with reduced fear of therapeutic procedures. In addition to parents and family, support of friends and contact with peers who have already overcome the disease is of great importance. Numerous researches are in support of this, it has been proved that optimistic patients are more successful in the treatment process, and recovery from disease is much more successful and faster.