Adverse effects on the pulmonary circulation in obstructive sleep disordered breathing (SDB) may place children with heart lesions affecting the right ventricle at increased risk for morbidity and mortality. We examined the distribution and effects of SDB in pediatric patients with tetralogy of Fallot (TOF). Families of 37 pediatric patients with TOF completed a survey of cardiac symptoms and school performance as well as a Pediatric Sleep Questionnaire (PSQ), a validated questionnaire for the screening of SDB in children 2-18 years of age. Medical records were reviewed for growth parameters, medical history, and most recent electrocardiogram (ECG) findings. Data from patients with SDB (PSQ score > or = 8, n = 14) were compared to data from patients without SDB (PSQ score < 8; n = 23). The prevalence of SDB in this population (38%) was significantly higher than the published prevalence of 5% in a healthy general pediatric population (p < 0.001). No significant difference was found in age, gender, or age and sex standardized body mass index between patients with or without SDB. No difference was seen in medication use or timing of surgical repair, whether primary or palliative. Patients with SDB had a significantly higher cardiac symptom score (p = 0.01) and increasing PSQ scores correlated with worsening cardiac symptom scores (p = 0.006). Increasing PSQ scores also correlated with worsening school performance (p = 0.001). No differences were seen in ECG data. The screened prevalence of SDB in the pediatric population with TOF is higher than in the general population; patients with TOF and SDB are more likely to have worse cardiac symptoms and poor school performance.