The purpose of this study was to define the selfAAC/Aa!AAconcept of children with cancer in comparison with healthy children and children with thalassaemia.Material-Method: 165 children with cancer were studied and compared to 417 healthy children and 212 children with thalassaemia of corresponding age. The control group with thalassaemia and the children in the study were children who had been admitted to two of Athens' largest paediatric hospitals - Pan. Agl. Kyriakou" and "Agia." Sophia'. Healthy controls were obtained from Athens schools. Interviews were conducted between the researcher with children from each group. The tool used for all children was the PiersAAC/AaAA Harris scale 'How I feel about me'. Data analysis revealed that children with cancer have a less positive image of themselves than the controls. Further analysis revealed that they have behavioural problems (p