The study objective was to describe polysomnographic findings in children with attention deficit hyperactivity disorder (ADHD) with diverse sleep problems. Polysomnographic data were retrospectively analyzed for 33 children (age 3-16 years) with ADHD who had sleep studies performed for diverse sleep complaints. Eight patients (24%) had obstructive sleep apnea, 10 (30%) had periodic limb movements of sleep, 8 (24%) had upper airway resistance syndrome, and 5 (15%) had obstructive hypoventilation. The ADHD group showed decreased sleep efficiency, increased arousal index, increased wake after sleep onset, decreased oxygen saturation nadir, and increased snoring, compared with control subjects. Compared with ADHD children without sleep disordered breathing, those who had sleep disordered breathing were significantly more obese and had more sleep architectural abnormalities (including increased sleep latency, increased rapid eye movement latency, increased wake after sleep onset, and increased arousal index with more oxygen desaturations), although total sleep time and sleep efficiency were not significantly different. Sleep disordered breathing and periodic limb movements of sleep appear to be common among children with ADHD who have symptoms of disturbed sleep.