Background: Although anxiety and, to a lesser extent, depression are highly prevalent in children, these problems are, difficult to identify. The Revised Anxiety and Depression Scale (RCADS) assesses self-reported symptoms of anxiety and depression in youth. Methods: The present study examined the factor structure, internal consistency, short-term stability, and validity including sensitivity to change of the RCADS in a multi-ethnic urban sample of 3636 Dutch children aged 8 to 13 years old. Results: Results indicate that the RCADS is a reliable and valid instrument. The original 6-factor structure was replicated to a fair extent in the present study (RMSEA = 0.048) and internal consistency was good (aαs = 0.70-0.96). ICCs for short-term stability were 0.76 to 0.86. Girls and children who indicated wishing to participate in a program targeting anxiety and depression had higher RCADS scores. Sensitivity to change analyses showed that the RCADS can detect changes in anxiety and depression symptoms in children who participated in a preventive intervention. The study showed low agreement between teacher and self-reported internalizing problems, even for children scoring above the 90 th percentile of the RCADS, indicating a high level of problems, emphasizing the need to also take child reports into account when screening for anxiety and depression in children. Conclusion: This study shows that the RCADS can yield reliable data on a diversity of anxiety disorders and depression in urban children aged 8-13 from very diverse ethnic backgrounds. Trial Registration: Netherlands Trial Register: NTR2397. Registered 30 June 2010.