Background: The role of calcium hydroxylapatite injection pharyngoplasty after failed sphincter pharyngoplasty surgery has not previously been described. We report our technique of injecting calcium hydroxylapatite into the pharyngoplasty site to add bulk to specific areas of the velopharyngeal port. Methods: A retrospective review of children undergoing calcium hydroxylapatite injection pharyngoplasty for persistent velopharyngeal insufficiency after sphincter pharyngoplasty was performed. Our surgical technique is described. Outcome measures included postoperative perceptual assessment of resonance, improvement in phoneme-specific nasometry scores, and rate of revision surgery. Results: Fourteen patients were included in the study. Improvement in hypernasality on perceptual assessment was noted in the majority of children (85.7%). The rate of achievement of normal resonance on perceptual analysis was 35.7%. A significant decrease in nasometry scores was noted for the following phonemes: /pa/, /sa/, /sha/, and /pi/. There were no intraoperative complications or immediate postoperative complications associated with calcium hydroxylapatite injection. Conclusions: Our early experience suggests that calcium hydroxylapatite injection after failed sphincter pharyngoplasty is a safe, minimally invasive technique with favorable short-term results.