To examine the effectiveness and cognitive effects of aripiprazole (APZ) in children with a primary diagnosis of attention-deficit/hyperactivity disorder (ADHD).Youths, ages 8-12 years, with a diagnosis of ADHD combined-type or ADHD predominately inattentive-type were enrolled into a 6-week, open-label pilot trial. Outcome measures included the ADHD Rating Scale-IV (ARS-IV), Clinical Global Impressions Scale (CGI), and Children's Global Assessment Scale (CGAS). The Conners' Continuous Performance Test II, Reading and Math Fluency subscales of the Woodcock-Johnson III Tests of Achievement, and the Stroop Color and Word Test were administered at baseline and end of study.Fourteen (9 males and 5 females) youths were diagnosed with ADHD-combined type, while 9 (5 males and 4 females) were diagnosed with ADHD-inattentive type. At a mean dose of 6.7 mg/day, end of study results showed overall significant improvement from baseline on ADHD and functional outcome measures. No significant differences in baseline performance at end of study were found on the cognitive measures. The most frequently reported adverse events were sedation (n = 18; 78.3%) and headache (n = 11; 47.8%).Although this was a brief pilot study with a small sample size, in this cohort, APZ led to clinical benefit in reducing ADHD symptoms and improving overall functioning. Of note, cognitive functioning did not appear to be negatively impacted by APZ treatment.