Psychosocial health issues are common among children with cardiac diagnoses. Understanding parent and child perceptions is important because parents are the primary health information source. Significant discrepancies have been documented between parent/child quality-of-life data but have not been examined among psychosocial diagnostic instruments. This study examined agreement and discrepancies between parent and child reports of psychosocial health and quality of life in the paediatric cardiology population. Children (n=50, 6–14 years) with diagnoses of CHDs (n=38), arrhythmia (n=5), cardiomyopathy (n=4), or infectious disease affecting the heart (n=3) were enrolled, completing one or more outcome measures. Children and their parents completed self-reports and parent proxy reports of quality of life – Pediatric Quality of Life Inventory – and psychosocial health – Behavioral Assessment Scale for Children (Version 2). Patients also completed the Multidimensional Anxiety Scale for Children. Associations (Pearson’s correlations, Intraclass Correlation Coefficients) and differences (Student’s t-tests) between parent proxy reports and child self-reports were evaluated. Moderate parent–child correlations were found for physical (R=0.33, p=0.03), school (R=0.43, p<0.01), social (R=0.36, p=0.02), and overall psychosocial (R=0.43, p<0.01) quality of life. Parent–child reports of externalising behaviour problems, for example aggression, were strongly correlated (R=0.70, p<0.01). No significant parent–child associations were found for emotional quality of life (R=0.25, p=0.10), internalising problems (R=0.17, p=0.56), personal adjustment/adaptation skills (R=0.23, p=0.42), or anxiety (R=0.07, p=0.72). Our data suggest that clinicians caring for paediatric cardiac patients should assess both parent and child perspectives, particularly in relation to domains such as anxiety and emotional quality of life, which are more difficult to observe.