We investigated the frequency and neurocognitive correlates of attention deficit hyperactivity disorder and traits of this disorder (ADHD/Traits) after childhood stroke and orthopedic diagnosis in medical controls. Twenty-nine children with focal stroke lesions and individually matched children with clubfoot or scoliosis were studied with standardized psychiatric, intellectual, academic, adaptive, executive, and motivation function assessments. Lifetime ADHD/Traits were significantly more common in stroke participants with no prestroke ADHD than in orthopedic controls (16/28 vs. 7/29; Fisher's Exact p < .02). Lifetime ADHD/Traits in the orthopedic controls occurred exclusively in males with clubfoot (7/13; 54%). Participants with current ADHD/Traits functioned significantly worse (p < .005) than participants without current ADHD/Traits on all outcome measures. Within the stroke group, current ADHD/Traits was associated with significantly lower verbal IQ and arithmetic achievement (p < .04), more nonperseverative errors (p < .005), and lower motivation (p < .004). A principal components analysis of selected outcome variables significantly associated with current ADHD/Traits revealed “impaired neurocognition” and “inattention-apathy” factors. The latter factor was a more consistent predictor of current ADHD/Traits in regression analyses. These findings suggest that inattention and apathy are core features of ADHD/Traits after childhood stroke. This association may provide clues towards the understanding of mechanisms underlying the syndrome. (JINS, 2003, 9, 815–829.)