BackgroundMental health problems among children and adolescents are a growing public health concern. Self-report questionnaires are pivotal for screening and early detection of mental health issues. We evaluate the psychometric properties and provide norm data of the 25-item child and 25-item parent-report versions of the Revised Child Anxiety and Depression Scale (RCADS).MethodsA random probability sample of 29,000 children and adolescents (ages 4-17) from the Swedish population registry was invited. Data collection occurred from September 2021 to January 2022, accompanied by one postal and four SMS reminders.ResultsParticipants (N = 7045, 48.98% girls) demonstrate that the RCADS-25 possesses relatively sound psychometric properties, albeit that the child-report version assessed with children and adolescents aged 8 to 17 years rendered relatively better psychometric properties (e.g., omega = 0.87-0.92, CFI = 0.89) compared with the parent-report version and the children 4 to 7 years old (e.g., omega = 0.72-0.82, CFI = 0.84).ConclusionThe RCADS-25 instruments may be used as an effective instrument for the initial assessment of anxiety and depression in children and adolescents in Sweden.