A review of 67 cases diagnosed as granulomatous, tuberculous or fungal mastitis revealed 5 cases which were similar, clinically and histopathologically, to the new entity of granulomatous mastitis described by Kessler and Wolloch. The 5 patients were young women of childbearing age, 4 with breast lesions clinically simulating carcinoma of the breast. Histopathological examination showed granulomata and abscess formation confined to the breast lobules. No acid-fast bacilli or fungi were demonstrated. Granulomatous mastitis may be caused by a chemical reaction associated with contraceptive pill therapy, or may have an auto-immune or infective aetiology.