Superiorly based pharyngeal flaps (PFs) are commonly used for the treatment of velopharyngeal insufficiency (VPI) in patients with cleft palate. However, failure may occur with recurrence of hypernasality and surgical revision may be necessary. Hemisphincter pharyngoplasty using either unilateral or bilateral posterior tonsillar pillars with the underlying palatopharyngeus muscle can be used to narrow the incompetent lateral portals. We retrospectively reviewed 22 patients diagnosed with VPI after PF surgery, who underwent hemisphincter pharyngoplasty from 1995 to 2007. Seventeen patients with complete speech assessment records were evaluated for the surgical outcome. Overall velopharyngeal function improvement was 88.2%. Symptoms of airway obstruction developed in 41% of the patients perioperatively. All of them improved gradually except 1 patient who needed continuous positive airway pressure mask treatment for obstructive sleep apnea. It is concluded that hemisphincter pharyngoplasty for narrowing of the incompetent portals is an effective treatment of VPI after PF.