Controversy exists as to whether AD/HD constitutes a developmental disability or merely represents an inconvenient pattern of behavior in schoolchildren. Documentation of functional deficits in children with AD/HD outside of school would provide support for the hypothesis that AD/HD is, in fact, a disability. Roizen and colleagues (Arch. Pediatr. Adolesc. Med. 148:1137,1995) have documented deficits on the Vineland Scales in school aged children with AD/HD. In this study we used the Wee-FIM to assess the functional independence of 43 children between the ages of 3.2 and 11.0 yrs(avg 6.53 yrs) who were evaluated in an outpatient program for children with behavior and learning disorders and who met DSM-4 criteria for AD/HD (avg CPRS hyperactivity index t = 84.3). Conners Parent Rating Scales and IQ scores were available for 26. We chose the Wee-FIM because it is concise, comprehensive, not discipline bound and has been standardized for children in this age group. It contains measures of self-care, sphincter control, transfers, locomotion, communication and social cognition. We hypothesized that the children would have average self-care and motor skills and have deficits in social cognition and communication. These children had significant deficits of total Wee-FIM score (t-test p < 0.0001). There were significant deficits in the subscales related to self-care, social cognition and communication (ANOVA F = 34.92, p< 0.001). In the 26 children for whom IQ, Wee-FIM, and Conners Parent Rating scores were available, stepwise regression analysis confirmed a significant correlation of total Wee-FIM and the self-care and social cognition subscales with the Learning Problems of the Conners but not age, IQ, or the other Conners subtests. These results confirm that young children with AD/HD have functional deficits in both self care skills and social skills and that these deficits are related more closely to inattention than disruptive behaviors, age or IQ. The Wee-FIM is a suitable tool to document these deficits. If these functional deficits can be confirmed in broader, community based, samples of children with AD/HD, remediation of functional deficits should be a focus of habilitation in children with AD/HD. (Sponsored in part by the Children's Guild of Buffalo.)