Sleep apnea in craniofacial surgery was investigated. Between January 1999 and December 2003, 18 patients were measured at an at least 6-month interval before and after surgery. Eight patients underwent palatoplasty for cleft palate, and the other 10 patients underwent orthognathic surgery, syndromic craniosynostosis, and postpharyngeal flap surgery. All patients included in the study demonstrated clinical signs of obstructive sleep apnea, such as snoring and cessation of breathing during sleep. An apnomonitor was used for presurgical and postsurgical sleep apnea status by measuring: 1) position during sleep; 2) percutaneous oxygen saturation; 3) respiratory analysis, such as the type of apnea-hypopnea, frequency of the events, and duration of apnea-hypopnea; 4) heart rate; and 5) snore analysis, such as trains, time, mean, and minimal and maximal amplifications. The apnea-hypopnea index (AHI) was significantly improved after surgery, especially in cases other than palatoplasty (7.4 +/- 8.73/h and 1.6 +/- 0.43/h, before and after surgery, respectively; P < 0.05 excluding palatoplasty). The percentage of snoring to total sleep was also improved significantly (22.4 +/- 19.74% and 9.0 +/- 8.54%, before and after surgery, respectively; P < 0.01 in all patients). Therefore, changes in sleep apnea parameters were elucidated in craniofacial surgery. Palatoplasty did not necessarily worsen the sleep apnea status, although there were snoring and anatomic abnormalities. Detachment of the pharyngeal flaps improved sleep apnea, and bimaxillary advancement was effective in normalizing sleep apnea.