BACKGROUND: The purpose of this study was to explore the differences in illness perception between children with cancer and other chronic diseases. A secondary aim was to examine the similarities and differences between the illness perception of these children and their parents. METHODS: The Revised Illness Perception Questionnaire (IPQ-R) was used to measure the children’s and parents’ illness perceptions. In this study, 184 children (ages 8-18 years) and their caregivers completed the questionnaires. RESULTS: This study shows that children with cancer feel that they have greater control over their treatment compared to the other two groups. The children’s parents have more pessimistic views of the illness than their children. CONCLUSION: Examinations of illness perceptions among paediatric cancer patients and their families are essential in designing psychosocial interventions for these families. The clinical value of our results can help better understand the cancer-specific features of illness perceptions.