OBJECTIVE: To develop and evaluate the usability of a serious game as an educational tool for promoting the health of children and adolescents with cancer. METHODS: The Contextualized Instructional Design (CID) methodology was applied to develop the serious game, structured in five stages: analysis, design, development, implementation, and evaluation. Usability assessment included children and adolescents diagnosed with cancer in a public federal referral hospital in a city in Northeastern Brazil, from April to June 2024. A sociodemographic questionnaire and the System Usability Scale with values ranging from 0 to 100 points were used. RESULTS: The serious game, entitled Oncoped: on the health journey, is an educational and playful board game that contains eight personalized Paper Toys, 35 houses, and 100 cards divided into multiple-choice questions about cancers, diagnosis, treatments, and challenges
and cards containing information and care tips. The usability assessment was carried out by 12 hospitalized children and 3 adolescents, who after using the game filled out the information on the scale, resulting in a mean score of 95.16 points. CONCLUSION: The serious game Oncoped: on the health journey is a fun and playful educational tool that provides effective and active learning. The educational technology received an excellent usability assessment among the game's target audience. Thus, it was found that the tool is innovative and has good acceptability for teaching and promoting the health of children and adolescents with cancer.