With the improvement of treatment results, the need for long-term follow-up, which is a part of total care, is increasing for childhood cancer patients. In addition, the necessity of the system is shown in the national cancer control. Given these factors, the “long-term-follow-up (LTFU) system development project for children and AYA (Adolescent and young adult) cancer patients” was started in 2017, which is aimed for medical professionals in charge of LTFU of childhood cancer patients to acquire the knowledge of LTFU and transitional medical care for childhood cancer and also to know how to operate the LTFU clinic. About 40% of the participants so far are nurses, and the background of the participants has changed. Result of the questionnaire survey of the training participants suggest that the nurses acquired knowledge that they previously did not sufficiently have, and they have also become more aware that childhood cancer patients who are undergoing growth and development need long-term involvement after diagnosis. Thus, participation in the training was evaluated to have a positive effect. On the other hand, the operation of LTFU clinics in clinical settings faces issues such as lack of manpower, and medical fees related to the establishment of an organizational structure. We have to consider future tasks so that the needs of those who have experienced childhood cancer can be better met.