STUDY OBJECTIVE: The impact of the broad spectrum of SDB severity on cognition in childhood has not been well studied. This study investigated cognitive function in children with varying severities of SDB and control children with no history of SDB. METHODS: One hundred thirty-seven children (75M) aged 7-12 were studied. Overnight polysomnography (PSG) classified children into four groups: primary snoring (PS) (n=59), mild obstructive sleep apnea syndrome (OSAS) (n=24), moderate/severe OSAS (n=19), and controls (n=35). Cognition was measured with a short battery of psychological tests including the Wechsler Abbreviated Scale of Intelligence (WASI), the Wide Range Achievement Test-3rd Edition (WRAT-3), the Rey Complex Figure Test (RCFT) and the Controlled Oral Word Association Test (COWAT). RESULTS: There was lower general intellectual ability in all children with SDB regardless of severity. Higher rates of impairment were also noted on measures of executive and academic functioning in children with SDB. CONCLUSIONS: Our findings suggest that neurocognitive deficits are common in children with SDB regardless of disease severity, highlighting that such difficulties may be present in children in the community who snore but are otherwise healthy; thus our results have important implications for the treatment of pediatric SDB.