Attention-deficit/hyperactivity disorder (ADHD) is frequently associated with learning disabilities. The present study examined the written composition of children with ADHD, which depends to a large degree on continuous self-regulation and attentional control skills for organizing information and maintaining the level of effort. Fifty children with ADHD and 50 normally developing children, matched on age and IQ, were assessed using a composition writing task. The results contribute to prior research findings by showing that the children with ADHD performed significantly worse than the comparison groups on the majority of the planning, translation, and revision process measures usually employed to assess the quality of written compositions. Deficiencies in executive functioning or poor linguistic and metalinguistic competence could account for the results found. More research is needed to clarify the underlying causes of the written composition performance profile of children with ADHD.