A child, who suffers from cancer, is a kind of a patient, who is too immature to understand the situation of his or her illness properly by attributing it the right meaning. During the treatment, a relation with parents helps the patient to estimate his or her situation. This survey aimed to present psychological functioning of a mother of a terminally ill child. The focus was directed on coping with stress, the sources of social support and the features of a family system. Additionally, the survey presents the marital relationship both from mother and father perspective. The results of the survey illustrate a great amount of resources such as: problem-focused coping with stress, marital communication based on support, commitment and mutual empathy. A properly functioning mother is undoubtedly a great help with dealing with her daughter’s illness.