Abbreviated home polysomnography may be an alternative to laboratory polysomnography in children but is not yet generally accepted, partly due to a lack of reference values. Also, there are no normative data on respiratory events obtained using nasal prongs. We determined the prevalence and frequency of central, obstructive, and mixed apneas and hypopneas in a populationbased sample of 50 children (mean age 10.1 years) using abbreviated home polysomnography and nasal prongs. We also determined the frequency of movements/arousals and body position changes. All children had central apneas. Obstructive apneas, mixed apneas, and hypopneas were found in 36%, 6%, and 14% of children, respectively. Average number of central, obstructive, and mixed apneas; hypopneas; movement/arousals; and body position changes per hour of sleep was 1.5, 0.1, 0.01, 0.02, 8.2, and 3.7, respectively. The corresponding cutoff values (mean plus 2 standard deviations or 95th centile) were 3.7, 0.7, 0.1, 0.2, 13.4, and 9.1, respectively. We did not find significant gender differences regarding any sleep variable under study. The presented reference values may help clinicians and researchers to improve the interpretation of abbreviated home polysomnography in school-age children. The gold standard for diagnosing sleep-disordered breathing (SDB) is full polysomnography in a sleep laboratory (1). Unattended home sleep studies using portable systems, however, are increasingly recognized as an alternative. Advantages include convenience, improved sleep quality, and costeffectiveness (2,3). Nonetheless, such studies are yet rarely used in the evaluation of pediatric SDB. One reason for this may be the lack of reference values.There are also no reference data for respiratory events in children measured by nasal prongs/pressure transducers, although these are more sensitive in detecting hypopnea and FL than thermal sensors (e.g. thermistor or thermocouples) (4,5). This is important because children are more likely than adults to have partial rather than complete upper airway obstruction (6).We, thus, aimed to establish reference values for respiratory and other sleep study variables obtained at home using portable devices and nasal prongs/pressure transducers. The current study was conducted as a part of a population-based crosssectional study on prevalence, risk factors, and consequences of various expressions of SDB in children (7-10). Primary school children were screened for signs and symptoms of SDB using parental questionnaires (8) and nocturnal home pulse oximetry (11). Children with and without signs and symptoms of SDB subsequently underwent nocturnal home polysomnography (8). In this report, we focus on the feasibility of performing unattended home sleep studies in children, the data quality achieved, and the presentation of reference values obtained from healthy school-age children. METHODS Subjects.The source population for the current study were subjects who had participated in the main study (8) and had (1) no history of habitual snorin...