Objective: To evaluate the diagnostic performance of the Attention Problem Scale of the Child Behavior Checklist (CBCL-APS) for the screening of Attention-Deficit/Hyperactivity Disorder (ADHD) in a sample of Brazilian children and adolescents. Methods: The CBCL-APS was given to 763 children and adolescents. Child psychiatrists using DSM-IV criteria confirmed the clinical diagnoses. Diagnostic performance was evaluated through Receiver-Operating Characteristic (ROC) curves. Results: Only moderate areas under the curve (AUC) were found for the general sample (AUC = 0.79; 95%CI = 0.76-0.82), and for the subsample of referred patients (AUC = 0.78; 95%CI = 0.74-0.82). The subsample of patients with ADHD of the combined type presented the largest AUC (AUC = 0.85; 95%CI = 0.82-0.88). Conclusion: Our findings concur with previous studies of different cultures demonstrating adequate diagnostic performance of the CBCL-APS for the screening of ADHD, especially of the combined type. (Contains 1 table and 1 figure.)