This study reviews the diagnosis and management of a consecutive series of 33 phyllodes tumours of the breast treated at The Royal Marsden Hospital, Sutton, between 1981 and 1992. The mean age of patients at presentation was 41 years (range 15-67 years). Tumours occurred equally in each breast and were significantly more common in the upper outer quadrant (chi 2 = 12.7, df = 3, P < 0.01). Clinical features (age, tumour size, palpation) and diagnostic investigations (mammography, ultrasound and fine needle aspiration cytology) were not sufficiently accurate to reliably make a preoperative diagnosis or predict histological type (benign, borderline or malignant). The diagnosis of phyllodes should be considered in patients aged 30-50 years with an apparent fibroadenoma. Of the patients, 66% underwent wide excision or mastectomy resulting in a favourable local recurrence rate of 14%. Our experience and review of the literature suggests that adequate local surgery is the treatment of choice and adjuvant treatments have no place in the routine management of phyllodes tumours. Regional lymph nodes were not involved in any of our patients and axillary dissection is not indicated.