This study evaluated the Planning, Attention, Simultaneous, and Successive (PASS) characteristics of children assessed for Attention Deficit/Hyperactivity Disorder (ADHD referred), children with a Reading Disability (RD), and children in Regular Education (RE). The Cognitive Assessment System (CAS) was used to assess PASS processes for the 119 children (48 in ADHDR; 23 in RD; and 48 in RE groups). The results showed that the ADHDR group had lower Planning scores than the RE group (effect size = 0.6). The RD group had lower Successive scores than the RE group (effect size = 1.1) and the ADHDR group (effect size = 1.2), and lower Simultaneous scores than the RE group (large effect size of 0.9). The implications for using PASS theory to assist in the identification process as well as for the design of interventions for children with ADHDR and children with RD are discussed. (Contains 3 tables and 2 figures.)