This study aimed to establish the psychometric properties of parent ratings on the Chinese version of the Swanson, Nolan, and Pelham IV scale (SNAP-IV) in a school-based sample of 3534 students in grades 1 to 8 from two cities and two suburbs in Taiwan and 189 children diagnosed with attention deficit/hyperactivity disorder (ADHD) (aged 6 to 15) consecutively recruited from a medical center in Taipei. Parents completed the Chinese versions of the SNAP-IV, Strengths and Difficulties Questionnaire, and Child Behavior Checklist. The Chinese SNAP-IV demonstrated similar three factor structure (Inattention, Hyperactivity/Impulsivity, and Oppositional) as its English version, and satisfactory test–retest reliability (intraclass correlation = 0.59∼0.72), internal consistency (alpha = 0.88∼0.90), concurrent validity (Pearson correlations = 0.56∼0.72), and discriminant validity. Boys scored higher than girls across the eight school grade levels. The SNAP-IV clearly distinguished children with ADHD from school-based participants. Comorbidity with oppositional defiant disorder/conduct disorder predicted higher SNAP-IV scores among children with ADHD. Our findings suggest that the Chinese SNAP-IV is a reliable and valid instrument for rating ADHD-related symptoms in both clinical and community settings in Taiwan. Copyright © 2008 John Wiley & Sons, Ltd.