In order to study the changing clinical pattern, diagnosis and surgical treatment of adenolymphoma, the records of all 57 patients with a confirmed histological diagnosis, made at Bristol Royal Infirmary between 1951 and 1984, were reviewed; in 3 patients (5 per cent) bilateral lesions had been found. No characteristics emerged in a review of the history and clinical examination which would have enabled a correct preoperative diagnosis to be made. During the period of study the incidence of adenolymphoma increased 24-fold. (Parotid pleomorphic salivary adenomas increased in incidence by only 42 per cent over the same period). Before 1965 all patients were men; between 1965 and 1975 the male to female ratio was 3:1; between 1975 and 1985, 1.6:1. Of the 48 patients who had a relevant history taken 45 were smokers (93.8 per cent). It is postulated that tobacco consumption is important in the development of adenolymphoma, and has produced the changes in incidence and sex ratio. Fine needle aspiration biopsy cytology (FNAB) afforded the only method of achieving a pre-operative diagnosis. This was successful in 64.7 per cent. Superficial parotidectomy induced a 43 per cent incidence of facial nerve neurapraxia. Controlled enucleation reduced this to 8 per cent. Enucleation is the procedure of choice for adenolymphoma but can only be employed with confidence if an exact pre-operative diagnosis is made.