OBJECTIVE: To investigate the impact of pharyngeal flap surgery for the management of velopharyngeal insufficiency on speech nasalance in terms of hyponasality in patients with cleft palate. MATERIAL AND METHODS: The study included 171 individuals of both genders, ages 6 to 57 years, who had repaired cleft palate and lip with residual velopharyngeal insufficiency and surgical indication for pharyngeal flap. Patients underwent nasometric evaluation of speech 1 to 4 days before surgery and, on average, 14 months after. Nasalance (the acoustic correlate of nasality) was determined by means of a nasometer while the patient read a set of five sentences containing predominantly nasal sounds, with a cutoff score of 43%. Values below this percentage suggest hyponasality. The comparison between pre- and postoperative nasalance values was performed using the Student "t" test, adopting a significance level of 5%. RESULTS: The mean nasalance scores decreased significantly (p < 0.001), from 57% preoperatively to 49% postoperatively. Although the mean values before and after surgery indicated the absence of hyponasality, the analysis of individual patients showed that 24% (41/171) began to present nasalance suggestive of hyponasality (<43%) after surgery. CONCLUSION: Hyponasality is a symptom that may occur after pharyngeal flap surgery and compromise speech. Its presence may be an indicator of upper airway obstruction caused by pharyngeal flap, and should be objectively investigated postoperatively.