Some patients with cleft lip/palate or isolated cleft palate seem to develop snoring as one possible symptom of an obstructive sleep apnoea syndrome after velopharyngoplasty (VPP). The aim of this paper was to determine whether there was a difference in the posterior airway space (PAS) between patients with a VPP who snored and those who did not. Four standard parameters were measured in lateral cephalograms of 20 patients with cleft lip/palate and isolated cleft palate, without diagnosis of further syndromes (e.g. Pierre Robin sequence), having undergone VPP, to examine the dimensions of the PAS. Data were set in correlation to the symptom of snoring, and compared with those of 40 patients without cleft undergoing orthodontic treatment and with 20 patients with cleft lip/palate or isolated cleft palate but not VPP. Metric parameters were significantly different after VPP in patients with clefting and snoring compared to the group of cleft patients without snoring. All patients with clefts exhibited at least in one dimension a constriction when compared to patients without clefting. In conclusion, cleft lip/palate and isolated cleft palate patients tend to have constrictions of the PAS. VPP may induce snoring and further narrowing. Recall and analysis for obstructive sleep apnoea syndrome should be mandatory.