This paper presents data comparing normal, learning-disabled (LD), emotionally disturbed (ED), and attention deficit/hyperactivity disorder (ADHD) or attention deficit disorder (ADD) children, from a total of 1,303 children used to standardize the Texas Features of Emotional Disturbance (Tx-FED), an assessment system involving parent and teacher reports of behavior occurring in school and home settings. The assessment tool measures areas such as acting out behaviors, affective behaviors, anxious behaviors, and pathognomic signs. Differences and similarities found across age subgroups (ages 6-11 and 12-19) and gender groups are presented. The ED and ADHD/ADD children's behaviors were seen by both teachers and parents to be almost identical. These children were seen to have the most deviant behavior compared to LD and normal children. Findings indicated that the Tx-FED does have utility as an assessment system. The measure was best able to discriminate between children without identified exceptionalities and children with ED or ADHD/ADD. (17 references; 9 tables/graphs) (JDD)