AbstractThe common breast fibroadenoma makes up between one‐third and one‐half of biopsies for benign breast disease. The contemporary view is that it is an abnormality of normal development and involution rather than a neoplasm. Various other benign conditions may be clinically indistinguishable, and histological confirmation was only obtained in 68% of 321 masses thought to be fibroadenomas. Short‐term (13–24 mo) follow‐up of 201 masses, thought to be fibroadenomas on clinical and cytological grounds, showed resolution in 31% and regression in a further 12%, this behavior being more common with single lesions; a further 32% increased in size. There have been no long‐term studies, but it is likely that most regress toward the end of a woman's reproductive years. Aspiration cytology can differentiate malignant from benign disease with great accuracy, but had impaired sensitivity (87%) and specificity (76%) in differentiating fibroadenoma from other benign processes in an analysis of 244 successful aspirates. While these lesions may be safely left in women under 25 years of age, only 19 (27%) of 70 women of this age group chose this option and excision remains the most frequent treatment.