Aims: To assess the validity of the Child Health Questionnaire (CHQ) as a screening tool for detecting 'at risk' emotional and behavioural maladjustment in children with diabetes, using the Behaviour Assessment System for Children (BASC) as a gold standard measure. Methods: CHQ and BASC were administered to 103 parents of children with Type 1 diabetes, aged 7-12 years. Sub-scales of the two measures were compared using Pearson's bivariate correlations. CHQ sensitivity and specificity cut-points were optimized against the BASC borderline category using receiver operating characteristic curves. Results: The BASC Externalizing Problems scale correlated strongly with CHQ Behaviour, Global Behaviour, Mental Health, Family Activities and Family Cohesion scales (r-values -0.68, -0.54, -0.51, -0.59, and -0.42, respectively). BASC Internalizing Problems scale correlated strongly with CHQ Behaviour, Mental Health and Family Cohesion scales (r-values -0.40, -0.43 and -0.45, respectively). Using receiver operating characteristic curve analysis, the CHQ Mental Health scale most effectively identified children classified as borderline on the BASC Internalizing Problems scale (sensitivity 87%, specificity 78%), while the CHQ Global Behaviour scale most effectively identified children classified as borderline on the BASC Externalizing Problems scale (sensitivity 73%, specificity 82%). Conclusions: Significant correlations were seen between the CHQ Global Behaviour and Mental Health scales and the BASC Externalizing and Internalizing scales, respectively. Sequential use of the CHQ, as a screening tool, followed by an established mental health measure such as the BASC, may help identify children with diabetes 'at risk' for chronic maladjustment and poor health outcomes.