Purpose: Velopharyngeal (VP) functional outcomes were analyzed in 155 consecutive sphincter pharyngoplasties (SP) to determine the rate of postoperative obstructive sleep apnea (OSA) symptoms, severity and treatment outcomes. Secondly, the study was designed to compare OSA rates following SP to published rates occurring after pharyngeal flap (42-58%). Methods: A retrospective review of 155 consecutive patients undergoing SP at a tertiary cleft center between 1990 and 2000 was performed. 98% of the operations were performed by or directly supervised by one of two senior cleft surgeons using the Jackson modification of the Hynes SP. Each patient included in the analysis (n=155) underwent standardized evaluation regimen including pre- and 3-month postoperative evaluation and screening for sleep apnea-associated symptoms. This screening consisted of evaluation by the VP team (speech/language pathologist, pediatric otolaryngologist and plastic surgeon) to identify patients with clinical features of obstructive sleep apnea, such as daytime somnolence, observed apnea, diminished concentration and severe snoring. All patients with clinical findings suggestive of OSA underwent monitored sleep study and further follow-up visits. Results: Of the 155 patients analyzed, 115 (75%) had complete correction of VPD with single SP surgery. 25% required SP revision, usually consisting of tightening of the SP port. During routine 3 month followup, OSA was confirmed in 13 (8%) of patients. Treatment consisted of observation in mild OSA (5) with subsequent resolution of symptoms, CPAP with early resolution (within 6 months) in 5, CPAP with late resolution (4 years) in 1, and SP revision or takedown in 3. Overall, rate of OSA requiring intervention was 5.8%. Significant OSA requiring surgical intervention was 1.9%. Five of the 13 total patients who developed OSA had undergone SP revision. Conclusions: Sphincter pharyngoplasty is a very effective means of improving velopharyngeal dysfunction. The risk of obstructive sleep apnea following SP is overall low (8%), is transient in the majority of patients, with overall need for surgical intervention at a low rate of 1.9%. This rate is much lower than published rates for pharyngeal flap and may result from the dynamic capabilities associated with sphincter pharyngoplasty.