Excessive daytime sleepiness (EDS) occurs frequently in adult patients with obstructive sleep apnea (OSA). However, the incidence of EDS in children with OSA is unknown. To determine overall daytime sleepiness in pediatric OSA, 54 children with OSA, 14 children with primary snoring (PS), and 24 controls (C) underwent an overnight diagnostic polysomnogram followed the next day by a multiple sleep latency test. The mean apnea index was 15.1 +/- 9.5 standard deviation in OSA, 1.1 +/- 0.5 in PS, and 0.1 +/- 0.3 in C. Mean sleep latencies were 23.7 +/- 3.0 minutes in C, 23.7 +/- 3.1 minute in PS, and 20.0 +/- 7.1 minute in OSA patients. However, only 7 children with OSA had mean sleep latencies <10 minutes. In addition, shorter sleep latencies were more likely to occur in more obese OSA patients and those with more severe apnea index, and oxyhemoglobin desaturation. Shortened sleep latencies occur in children with OSA, but EDS is infrequent and tends to develop among more severe and/or obese patients.