Sialocele is an uncommon complication of parotidectomy. Most cases resolve after conservative therapy consisting of repeated aspiration and pressure dressing. The condition is, however, occasionally resistant to such therapy. We report on a 52-year-old Chinese man who had a 10-year history of right parotid swelling. Following fine-needle aspiration cytology, Warthin’s tumour was diagnosed, but after elective parotidectomy, a swelling developed and parotid sialocele was diagnosed. Botulinum toxin type A was given after the sialocele had persisted for almost 3 weeks after surgery, and after conservative management had been tried; the sialocele disappeared after two doses of treatment. Botulinum toxin therapy was thus an effective method of treating persistent sialocele.