Background: Patient compliance in carrying out blood transfusions is important in the management of people with thalassemia. The family has a strong influence on determining treatment, the support provided is instrumental support, assessment support, informational support and emotional support. To determine the relationship between family support and blood transfusion compliance in children suffering from thalassemia major. Method: This research is quantitative research that is correlational in nature. The sampling technique in this research used total sampling, where samples were taken from the entire available population, namely 55 people. This study used measuring instruments in the form of a family support questionnaire and an observation sheet by looking at the thalassemia patient's book in the room. Results: Most or around 90.9% of children with thalassemia are guardians in the Children's Care Room at Pasteur Regional Hospital, Bandung, and receive good family support. Most or around 65.5% of children suffering from thalassemia major in the Children's Care Room at Pasteur Hospital Bandung are obedient to undergoing blood transfusions. Conclusion: There is a relationship between family support and blood transfusion compliance in children with thalassemia in the Children's Care Room at Pasteur Hospital, Bandung, with a p-value of 0.043.