Eight patients (aged 8 to 22 years) with the Pierre Robin syndrome underwent sleep studies. Seven demonstrated significant although minor degrees of increased sleep disturbances and apneas, and less time spent in the rapid-eye-movement (REM) stage of sleep. One patient who had previously undergone mandibular corrective surgery had major sleep abnormalities (central apnea index of 81.7 although an obstructive sleep apnea index of only 1.9). The patients had small mandibles, as demonstrated by lateral cephalometric roentgenography, and mildly increased right ventricular diastolic dimensions, as shown by M-mode echocardiography. Snoring was present in all of these patients and in 13 of 22 patients questioned from our Pierre Robin clinic. We conclude that minor abnormalities in sleep, mandibular size, and right ventricular size persist well into adolescence in the majority of patients with Pierre Robin syndrome. These appear to be clinically insignificant; however, a small percentage of such patients may continue to have major sleep disturbances.