Background and context: It is known the chances of healing in developed countries might be of 90%, depending on the type of tumor and, especially, its early diagnosis. In Brazil, cancer is the leading cause of death by disease among ages from 1 to 19, and because it is rare, health professionals have difficulties in diagnosing and referring cases to treatment. Aim: The “Unidos pela Cura” aims to promote early diagnosis of childhood cancer in Rio de Janeiro in a coresponsible and integrated way to the principles of Brazilian Unified Health System (universalization, equity and integrality). Strategy/Tactics: This initiative included the Desiderata Institute as the leader of civil society organization, having as its bases: i) Mobilization of managers from the government, heads and professionals of the pediatric oncology services, health practitioners (primary care) and social organization to identify the main problem with pediatric oncology in the public system and to collectively think solutions. The identified problem was related to the early diagnosis; ii) Knowledge about the identified problem, with studies: one pointed out the main epidemiologic trends of childhood cancer in the state of Rio de Janeiro ( Koiffman, 2004 ); and another showed the system problems by revealing that suspicions of childhood cancer took an average of 60 days to be investigated when they arrived from primary care ( Brito, 2005 ); iii) Advocacy: the collective construction of coresponsibilities and priorities regarding childhood cancer in a term of commitment, and marked the definition of the initiative as public policy; and iv) Communication: bulletins with the results of the Unidos pela Cura are to be annually produced and sent to managers and health professionals to monitor cases and disseminate the results. Program/Policy process: Unidos pela Cura is a collective and coresponsible initiative to promote the early diagnosis of childhood cancer, created in 2005 and organized into three axes: i) Education - training health professionals in the family health strategy for cancer suspicion; ii) Flow - organization of referral flow and referral of suspected cases of childhood cancer from primary care to specialized hospitals to start the diagnostic investigation within 72 hours; and iii) Information - online system for monitoring suspected cases referred by primary care until diagnostic confirmation, with annual results disclosure. Outcomes: As results, the Unidos pela Cura has been included in the State Cancer Care Plan (2018-2021) and the Municipal Health Plan (2009-2012); 535 doctors and 3038 professionals from the family health strategy; 1311 children and adolescents were referred and 127 confirmed cases of cancer; 37 meetings of the managing group of Unidos pela Cura, among others. What was learned: Collaborative actions between society and governments can contribute to better outcomes and chances of cure.