Objective: The authors investigate differences in the neuropsychological and behavioral profiles of two groups of children with ADHD, one with predominantly inattentive subtype of ADHD (PI) and high sluggish cognitive tempo (SCT; n = 19) and another formed by the rest of the sample (children with ADHD combined subtype and children with PI and low SCT scores; n = 68). Method: Instruments included Wechsler Intelligence Scale for Children and subtests from Developmental Neuropsychological Assessment, Conners’ Continuous Performance Test, Behavior Rating Inventory of Executive Function, and Achenbach’s Child Behavior Checklist for ages 6 to 18. Results: PI with high SCT had fewer problems with sustained attention, and more internalizing problems, anxiety/depression, and withdrawn/depressed behavior, and more executive problems with self-monitoring than the rest of the ADHD sample. Conclusion: This study supports revising subtype’s criteria and further studying the hypothesis that ADHD with high SCT constitutes a separate clinical entity. (J. of Att. Dis. 2012; XX(X) 1-XX)