Persistent hypernasality after adenotonsillectomy is not an uncommon complication, occurring in approximately 1 in 1,500 procedures. The primary aetiological factor is an underlying congenital abnormality of the palate which is unmasked by removing the adenoidal tissue. It is possible to identify many of those at risk by careful history taking and clinical examination. For those patients in whom this complication occurs spontaneous improvement can be expected for up to one year afterwards, and speech therapy may be useful. Surgical intervention is necessary in up to 50% of cases.