The aim of this research was to gain insight into the experiences of assistants professionals about changes in the functioning of the family and the need for support in families facing a child's malignant disease. The research was conducted with 6 participants, three psychologists and three social workers. One participant was a hospital employee, while all others were employees of associations working with families with children with malignancy or are external associates of the hospital. Data were collected by the method of semi-structured interview, with an average duration of about 40 minutes. The data were processed by the method of thematic analysis and the results show that the reactions to the existence of malignant disease in a child are mainly conditioned by emotional responses, are different over time and depending on the family member. When there are changes in the functioning of the family, there are changes in the internal organization of the family, the organization of the environment and changes in the environment through relocation, the relationship between the parents and the sick child changes. A mitigating factor in coping is positive communication with medical staff, strong prior connection of family members, systematic professional and financial support to families and the personal strength of each individual. There is a certain level of service available to families, mostly provided by associations. The need to develop support that will be more accessible and systematic and the need to improve the wider social attitude towards malignant diseases were emphasized.