The aim of this study was to examine functional attention and executive deficits present in everyday living in a large sample of children with neurofibromatosis type 1 (NF1). Data are presented from 199 children with NF1 and 55 unaffected sibling controls who were administered the Behavior Rating Inventory of Executive Function (BRIEF) and Conners' ADHD DSM-IV Scales (CADS). Convergent validity was examined by correlating scale scores from these functional measures with scores from traditional cognitive measures of attention and executive function. Results indicated global functional attention and executive deficits in children with NF1. Relationships between functional impairments and scores on cognitive measures were inconsistent; at best, the magnitude of these relationships was in the moderate range, yet there was also a lack of association between many cognitive tasks and the functional skills they purport to assess. Findings suggest that cognitive and functional measures may tap different constructs and that neuropsychological evaluations should be supplemented with functional assessment tools to provide a more accurate and sensitive encapsulation of a child's strengths and weaknesses to guide remediation programs.