AIM: To evaluate the psychometric properties of the Child and Adolescent Intellectual Disability Screening Questionnaire (CAIDS-Q) in paediatric neurodevelopment clinics. METHOD: Participants were 181 children (aged 6-18y) attending paediatric services in Scotland, divided into three age groups according to previous CAIDS-Q standardization cut-off scores. Fifty-four children (37 males, 17 females; mean age 117mo [SD 29.9mo]) met the criteria for intellectual disability and 127 did not (88 males, 39 females; mean age 120.1mo [SD 32.7mo]). A number of psychometric properties of the CAIDS-Q were evaluated, including test-retest and interrater reliability, convergent validity, sensitivity, specificity, and positive and negative predictive values based on existing cut-off scores. RESULTS: Significant positive relationships were found for all three age groups between CAIDS-Q scores and measures of intellectual and adaptive functioning. Test-retest reliability ranged from 'moderate' to 'almost perfect', whereas interrater reliability ranged from 'fair' to 'almost perfect'. Sensitivity and positive predictive value were 100% for all groups and specificity was between 83% and 94%, depending on age. Negative predictive values ranged from 75% to 91%. INTERPRETATION: The CAIDS-Q appears to show psychometric properties that support its use as a screen for intellectual disability in paediatric neurodevelopmental settings. WHAT THIS PAPER ADDS: The Child and Adolescent Intellectual Disability Screening Questionnaire showed good psychometric properties. It identified all participating children who met the criteria for intellectual disability. Between 83% and 94% of children without intellectual disability were also correctly identified.