The purpose of this study was to investigate the effects of velopharyngeal flap surgery on speech and its relation with the activity in the lateral pharyngeal walls. Videofluoroscopic recordings made before and after operation were used in this retrospective study, which comprised 28 patients who had pharyngeal flap surgery between 5:5 and 14:3 (mean 8:6) years:months of age at the Sahlgrenska University Hospital, Göteborg, Sweden. Twenty-four patients had different types of clefts and four had velopharyngeal impairment (VPI) without a cleft palate. Eleven had additional malformations. Speech and activity in the lateral pharyngeal walls were perceptually preoperatively and postoperatively. The study confirmed that patients with VPI can be helped by a velopharyngeal flap operation. There seemed to be a relation with the activity in the lateral pharyngeal wall and speech. The later the postoperative assessment, the better the speech, but the age at operation did not affect the result. The impact of additional anomalies and syndromes should be investigated further.